Don't connect to the DB when precompiling assets.

See
https://devcenter.heroku.com/articles/rails3x-asset-pipeline-cedar#troubleshooting

config/application.rb

@@ -58,5 +58,8 @@ module Growstuff
 
     # Version of your assets, change this if you want to expire all your assets
     config.assets.version = '1.0'
+
+    # Don't try to connect to the database when precompiling assets
+    config.assets.initialize_on_precompile = false
   end
 end