diff --git a/inc/activities.php b/inc/activities.php
index 87c5612..6976b15 100644
--- a/inc/activities.php
+++ b/inc/activities.php
@@ -85,24 +85,4 @@ function create_local_activity( $activity ) {
     }
     return $activity;
 }
-
-function create_activities_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_activities (
-            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
-            activity TEXT NOT NULL
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-    $wpdb->query(
-        "
-        CREATE UNIQUE INDEX ACTIVITIES_ACTIVITYPUB_ID_INDEX
-        ON pterotype_activitypub_activities (activitypub_id);
-        "
-    );
-}
 ?>
diff --git a/inc/actors.php b/inc/actors.php
index ea42643..f028cd5 100644
--- a/inc/actors.php
+++ b/inc/actors.php
@@ -61,20 +61,6 @@ function get_user_actor( $user ) {
     return $actor;
 }
 
-function create_actors_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_actors(
-            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            slug VARCHAR(64) UNIQUE NOT NULL,
-            type VARCHAR(64) NOT NULL
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-}
-
 /*
 For every user in the WP instance, create a new actor row for that user
 if it doesn't already exist
diff --git a/inc/blocks.php b/inc/blocks.php
index 62fe807..f1ddff3 100644
--- a/inc/blocks.php
+++ b/inc/blocks.php
@@ -17,19 +17,4 @@ function create_block( $actor_id, $blocked_actor_url ) {
         return new \WP_Error( 'db_error', __( 'Error inserting block row', 'pterotype' ) );
     }
 }
-
-function create_blocks_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_blocks(
-            actor_id INT UNSIGNED NOT NULL,
-            blocked_actor_url TEXT NOT NULL,
-            FOREIGN KEY blocks_actor_fk(actor_id)
-                REFERENCES pterotype_activitypub_actors(id)
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-}
 ?>
diff --git a/inc/db.php b/inc/db.php
new file mode 100644
index 0000000..d0a95aa
--- /dev/null
+++ b/inc/db.php
@@ -0,0 +1,120 @@
+<?php
+/*
+Poor man's migration system
+*/
+namespace db;
+
+/*
+It's okay to add new queries to this function, but don't ever delete queries.
+*/
+function run_migrations() {
+    $previous_version = get_option( 'pterotype_previously_migrated_version' );
+    if ( !$previously_migrated_version ) {
+        $previous_version = '0.0.0';
+    }
+    if ( version_compare( $previous_version, PTEROTYPE_VERSION, '<' ) ) {
+        if ( version_compare( $previous_version, '0.0.1', '<' ) ) {
+            migration_0_0_1();
+        }
+    }
+    update_option( 'pterotype_previously_migrated_version', PTEROTYPE_VERSION );
+}
+
+function migration_0_0_1() {
+    global $wpdb;
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_activities (
+            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
+            activity TEXT NOT NULL
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE UNIQUE INDEX ACTIVITIES_ACTIVITYPUB_ID_INDEX
+        ON pterotype_activitypub_activities (activitypub_id);
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_objects (
+            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
+            object TEXT NOT NULL
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE UNIQUE INDEX OBJECT_ACTIVITYPUB_ID_INDEX
+        ON pterotype_activitypub_objects (activitypub_id);
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_outbox (
+            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+            actor_id INT UNSIGNED NOT NULL,
+            activity_id INT UNSIGNED NOT NULL,
+            FOREIGN KEY outbox_activity_fk(activity_id)
+                REFERENCES pterotype_activitypub_activities(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_actors(
+            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+            slug VARCHAR(64) UNIQUE NOT NULL,
+            type VARCHAR(64) NOT NULL
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_likes (
+            actor_id INT UNSIGNED NOT NULL,
+            object_id INT UNSIGNED NOT NULL,
+            PRIMARY KEY (actor_id, object_id),
+            FOREIGN KEY likes_actor_fk(actor_id)
+                REFERENCES pterotype_activitypub_actors(id),
+            FOREIGN KEY likes_object_fk(object_id)
+                REFERENCES pterotype_activitypub_objects(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_following(
+            actor_id INT UNSIGNED NOT NULL,
+            object_id INT UNSIGNED NOT NULL,
+            state VARCHAR(64) NOT NULL,
+            PRIMARY KEY (actor_id, object_id),
+            FOREIGN KEY following_actor_fk(actor_id)
+                REFERENCES pterotype_activitypub_actors(id),
+            FOREIGN KEY following_object_fk(object_id)
+                REFERENCES pterotype_activitypub_objects(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+    $wpdb->query(
+        "
+        CREATE TABLE pterotype_activitypub_blocks(
+            actor_id INT UNSIGNED NOT NULL,
+            blocked_actor_url TEXT NOT NULL,
+            FOREIGN KEY blocks_actor_fk(actor_id)
+                REFERENCES pterotype_activitypub_actors(id)
+        )
+        ENGINE=InnoDB DEFAULT CHARSET=utf8;
+        "
+    );
+}
+?>
diff --git a/inc/following.php b/inc/following.php
index 2bdcb9e..dbe108c 100644
--- a/inc/following.php
+++ b/inc/following.php
@@ -14,23 +14,4 @@ function request_follow( $actor_id, $object_id ) {
         )
     );
 }
-
-function create_following_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_following(
-            actor_id INT UNSIGNED NOT NULL,
-            object_id INT UNSIGNED NOT NULL,
-            state VARCHAR(64) NOT NULL,
-            PRIMARY KEY (actor_id, object_id),
-            FOREIGN KEY following_actor_fk(actor_id)
-                REFERENCES pterotype_activitypub_actors(id),
-            FOREIGN KEY following_object_fk(object_id)
-                REFERENCES pterotype_activitypub_objects(id)
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-}
 ?>
diff --git a/inc/init.php b/inc/init.php
index e40b9d8..c224427 100644
--- a/inc/init.php
+++ b/inc/init.php
@@ -1,14 +1,9 @@
 <?php
 namespace init;
 
-require_once plugin_dir_path( __FILE__ ) . '/outbox.php';
 require_once plugin_dir_path( __FILE__ ) . '/api.php';
-require_once plugin_dir_path( __FILE__ ) . '/objects.php';
-require_once plugin_dir_path( __FILE__ ) . '/activities.php';
 require_once plugin_dir_path( __FILE__ ) . '/actors.php';
-require_once plugin_dir_path( __FILE__ ) . '/likes.php';
-require_once plugin_dir_path( __FILE__ ) . '/following.php';
-require_once plugin_dir_path( __FILE__ ) . '/blocks.php';
+require_once plugin_dir_path( __FILE__ ) . '/db.php';
 
 add_action( 'rest_api_init', function() {
     \api\register_routes();
@@ -20,13 +15,7 @@ add_action( 'user_register', function( $user_id ) {
 } );
 
 add_action( 'pterotype_init', function() {
-    \activities\create_activities_table();
-    \objects\create_object_table();
-    \outbox\create_outbox_table();
-    \actors\create_actors_table();
+    \db\run_migrations();
     \actors\initialize_user_actors();
-    \likes\create_likes_table();
-    \following\create_following_table();
-    \blocks\create_blocks_table();
 } );
 ?>
diff --git a/inc/likes.php b/inc/likes.php
index b25dae4..480944c 100644
--- a/inc/likes.php
+++ b/inc/likes.php
@@ -7,22 +7,4 @@ function create_like( $actor_id, $object_id ) {
         'pterotype_activitypub_likes', array( 'actor_id' => $actor_id, 'object_id' => $object_id )
     );
 }
-
-function create_likes_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_likes (
-            actor_id INT UNSIGNED NOT NULL,
-            object_id INT UNSIGNED NOT NULL,
-            PRIMARY KEY (actor_id, object_id),
-            FOREIGN KEY likes_actor_fk(actor_id)
-                REFERENCES pterotype_activitypub_actors(id),
-            FOREIGN KEY likes_object_fk(object_id)
-                REFERENCES pterotype_activitypub_objects(id)
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-}
 ?>
diff --git a/inc/objects.php b/inc/objects.php
index 1d64828..e0c1285 100644
--- a/inc/objects.php
+++ b/inc/objects.php
@@ -142,24 +142,4 @@ function delete_object( $object ) {
     }
     return $res;
 }
-
-function create_object_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_objects (
-            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            activitypub_id VARCHAR(255) UNIQUE NOT NULL,
-            object TEXT NOT NULL
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-    $wpdb->query(
-        "
-        CREATE UNIQUE INDEX OBJECT_ACTIVITYPUB_ID_INDEX
-        ON pterotype_activitypub_objects (activitypub_id);
-        "
-    );
-}
 ?>
diff --git a/inc/outbox.php b/inc/outbox.php
index bd0e6bb..459d73f 100644
--- a/inc/outbox.php
+++ b/inc/outbox.php
@@ -146,20 +146,4 @@ function wrap_object_in_create( $actor_slug, $object ) {
     );
     return $activity;
 }
-
-function create_outbox_table() {
-    global $wpdb;
-    $wpdb->query(
-        "
-        CREATE TABLE IF NOT EXISTS pterotype_activitypub_outbox (
-            id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-            actor_id INT UNSIGNED NOT NULL,
-            activity_id INT UNSIGNED NOT NULL,
-            FOREIGN KEY outbox_activity_fk(activity_id)
-                REFERENCES pterotype_activitypub_activities(id)
-        )
-        ENGINE=InnoDB DEFAULT CHARSET=utf8;
-        "
-    );
-}
 ?>
diff --git a/pterotype.php b/pterotype.php
index ce0fb1e..d711fca 100644
--- a/pterotype.php
+++ b/pterotype.php
@@ -4,7 +4,10 @@ Plugin Name: Pterotype
 */
 require_once plugin_dir_path( __FILE__ ) . 'inc/init.php';
 
+define( 'PTEROTYPE_VERSION' '0.0.1' );
+
 function pterotype_init() {
+    update_option( 'pterotype_version', PTEROTYPE_VERSION );
     do_action( 'pterotype_init' );
 }