Trial code to remove 'another command is already in progress'

This code makes the process wait for all of the Ajax calls end.
https://gist.github.com/josevalim/470808
http://qiita.com/kntmrkm/items/a02f5694843fee97763e
Add dependency restriction of twitter-bootstrap-rails
Merge remote-tracking branch 'origin/get_rid_of_pg_error'