CON-548: Added city_id field and index to wikia_hub_modules table
CON-548: Added city_id field to wikia_hub_modules and primary_key
CON-548: Remove city_id from primary key
CON-548: Added city_id to primary key
CON-548: Added index to support hubs v3
Merge pull request #2752 from Wikia/CON-548

CON-548: Added city_id field and index to wikia_hub_modules table