Remove abandoned GroupMembers

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	db/schema.rb

db/migrate/20150429002313_remove_abandoned_group_members_records.rb

+class RemoveAbandonedGroupMembersRecords < ActiveRecord::Migration
+  def change
+    execute("DELETE FROM members WHERE type = 'GroupMember' AND source_id NOT IN(\
+        SELECT id FROM namespaces WHERE type='Group')")
+  end
+end

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: 20150417122318) do
+ActiveRecord::Schema.define(version: 20150429002313) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"