Actually test on Ruby 2.0
Actually test on Ruby 2.0

The README states the Moped is tested on Ruby 2.0, but it isn’t
actually (at least not on CI). This remedies that.
jonhyman/moped,fcruxen/moped,newsdev/moped,ramen-dev/moped,agis-/moped,johnnytomcat/moped,aijanai/moped,mongoid/moped,drobune/moped,crashlytics/moped,sferik/moped,wandenberg/moped