I just updated from rails 3 to rails 4. Everything works locally, but deployed on heroku, I get the following error:
ActionView::Template::Error (uninitialized c
See this comment from Moped's author as of Moped 2.0.0 (which is the version , as of this writing, used as the driver in mongoid 4.0.0):
Moped's BSON implementation has been removed in favor of the 10gen bson gem 2.0 and higher. All Moped::BSON references should be changed to just BSON.
https://github.com/mongoid/moped/blob/master/CHANGELOG.md