wercker/box-rvm — pull request #1 by 1syo (2014-01-08 15:40:03+00:00)
Title: update bundler

Bundler 1.5.0 and Ruby 2.1.0 does not find json 1.8.1 gems.
And this problem has resolved on bundler 1.5.1.

See also
https://github.com/bundler/bundler/issues/2780