diff --git a/db/migrate/20140921104907_remove_stale_memberships.rb b/db/migrate/20140921104907_remove_stale_memberships.rb
new file mode 100644
index 00000000..ca55535c
--- /dev/null
+++ b/db/migrate/20140921104907_remove_stale_memberships.rb
@@ -0,0 +1,5 @@
+class RemoveStaleMemberships < ActiveRecord::Migration
+  def up
+    Membership.where("group_id NOT IN (?)", Group.ids).delete_all
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index c8e9c41e..eb038a10 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20140521142651) do
+ActiveRecord::Schema.define(version: 20140921104907) do
 
   create_table "article_categories", force: true do |t|
     t.string "name",        default: "", null: false