Just a quick note for searchers.
Maybe you got this error:
Gem::LoadError: You have already activated rake 10.1.0, but your Gemfile requires rake 10.0.0. Using bundle exec may solve this. ~/.rvm/gems/ruby-2.0.0-p0@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:33:in `block in setup' ~/.rvm/gems/ruby-2.0.0-p0@global/gems/bundler-1.3.4/lib/bundler/runtime.rb:19:in `setup' ~/.rvm/gems/ruby-2.0.0-p0@global/gems/bundler-1.3.4/lib/bundler.rb:120:in `setup' ~/.rvm/gems/ruby-2.0.0-p0@global/gems/bundler-1.3.4/lib/bundler/setup.rb:17:in `<top (required)>' ~/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:110:in `require'
It’s easy to fix. Just run:
$ bundle update rake # or whatever your gem is called
If this does not work, you can use bundle exec as the error says.
