Source: http://unix.stackexchange.com/a/224974
rvm list
=> ruby-2.2.0
.bashrc
export GEM_HOME=/home/deployer/.rvm/gems/ruby-2.2.0
export GEM_PATH=/home/deployer/.rvm/gems/ruby-2.2.0:/home/deployer/.rvm/gems/ruby-2.2.0@global
export RAILS_ENV=production
export RAKE_ENV=production