Create load_models().

So all models are ready when connecting to the db and so
our "db" object has all models listed on it, create a
function to load all models from the media_types, etc. Call
it in setup_database()

Problem: This gives celery warnings, because celery is
imported before being setup properly. No idea how to fix
this now. So media-type loading is excluded from
load_models for now.

mediagoblin/init/__init__.py

@@ -24,7 +24,7 @@ from mediagoblin.init.config import (
 from mediagoblin import mg_globals
 from mediagoblin.mg_globals import setup_globals
 from mediagoblin.db.open import setup_connection_and_db_from_config, \
-    check_db_migrations_current
+    check_db_migrations_current, load_models
 from mediagoblin.workbench import WorkbenchManager
 from mediagoblin.storage import storage_system_from_config
 
@@ -56,6 +56,9 @@ def setup_global_and_app_config(config_path):
 def setup_database():
     app_config = mg_globals.app_config
 
+    # Load all models for media types (plugins, ...)
+    load_models(app_config)
+
     # Set up the database
     connection, db = setup_connection_and_db_from_config(app_config)