Add Ruby 2.1.2 to CI.
Add Ruby 2.1.2 to CI.

benizi/tmuxinator,guyhughes/tmuxinator,cinaeco/tmuxinator,pczarn/tmuxinator,guyhughes/tmuxinator,sachin21/tmuxinator,benizi/tmuxinator,podung/tmuxinator,J3RN/tmuxinator,adamstrickland/tmuxinator,sjfloat/tmuxinator,tmuxinator/tmuxinator,magicalbanana/tmuxinator,danimad/tmuxinator,adamstrickland/tmuxinator,ethagnawl/tmuxinator,jasonchaffee/tmuxinator,azat/tmuxinator,klaxalk/tmux,ethagnawl/tmuxinator,marcinmagier/tmuxinator,jlipps/tmuxinator,benizi/tmuxinator,danimad/tmuxinator,adamstrickland/tmuxinator,sachin21/tmuxinator,azat/tmuxinator,sachin21/tmuxinator,klaxalk/tmux,marwensaid/tmuxinator,pczarn/tmuxinator,guyhughes/tmuxinator,klaxalk/tmux,sideci-sample/sideci-sample-tmuxinator,danimad/tmuxinator,marcinmagier/tmuxinator,cinaeco/tmuxinator,cinaeco/tmuxinator,tmuxinator/tmuxinator,J3RN/tmuxinator,magicalbanana/tmuxinator,marwensaid/tmuxinator,podung/tmuxinator,ethagnawl/tmuxinator,sideci-sample/sideci-sample-tmuxinator,klaxalk/tmux,marwensaid/tmuxinator,sjfloat/tmuxinator,podung/tmuxinator,azat/tmuxinator,sjfloat/tmuxinator,marcinmagier/tmuxinator,jlipps/tmuxinator,jasonchaffee/tmuxinator,aMoniker/tmuxinator,aMoniker/tmuxinator,tmuxinator/tmuxinator,J3RN/tmuxinator,aMoniker/tmuxinator,jasonchaffee/tmuxinator,pczarn/tmuxinator,jlipps/tmuxinator,magicalbanana/tmuxinator,klaxalk/tmux