Adds/modifies associations between CustomCollection <=> Org and CustomCollection <=> User.
Adds migration to change `custom_collections`.`user_id` to `custom_collections`.`owner_id` and add column `custom_collections`.`owner_type`, necessary for polymorphic associations.
Adds factory for Org instances.
Changes references to `user`, and `user_id` to `owner`, `owner_id`, and `owner_type` where needed.
Removes user_id from Custom Collection add/edit form, and supposes logged in user as the owner when creating new Custom Collection as non-admin user.
Removes vanity url's for scholar's custom collections for now. I'd like to either rework, or get a better understanding of how this is being done.
Changes :custom_collection factory to use FactoryGirl's `association` method, instead of setting foreign keys, for the `owner`.
Documents Ability::custom_permissions method, which touches on some Hydra stuff.
Changes  to  for  and  models in anticipation of many-to-many between CustomCollections and Users coming up next.