Revert "Use Ruby 2.1."
Revert "Use Ruby 2.1."

This reverts commit a6bde79b86eed8f51b363cbb520f04096274bf34.

nikhilmat/helpful-web,asm-helpful/helpful-web,asm-helpful/helpful-web,nikhilmat/helpful-web,asm-helpful/helpful-web,asm-helpful/helpful-web,nikhilmat/helpful-web