To make mercury-rails be precompiled I had to add this to production.rb:
config.assets.precompile += %w( mercury.js mercury.css mercury_overrides.css )
This should be done automatically by including the gem mercury-rails
See also: http://stackoverflow.com/questions/8056279/error-trying-use-mercury-wysiwyg-editor-in-rails-3-1-app-on-heroku
just added a commit that follows what you suggest here. I don't have a prod environment to fully confirm, but it seems likely to resolve the issue. I set you as author, because I didn't do much besides take what you had here.
adjustments to the engine to include mercury in precompiled assets (i…
…n all environments). fixes #73
this is still not working for us