Update Travis rubies.
Update Travis rubies.

cysjonathan/coursemology2,harryggg/coursemology2,harryggg/coursemology2,harryggg/coursemology2,Coursemology/coursemology2,cysjonathan/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,cysjonathan/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2,Coursemology/coursemology2