Lock mustache gem to a version that supports ruby 1.9.3
Lock mustache gem to a version that supports ruby 1.9.3

pkang/foodcritic,coderanger/foodcritic,odcinek/foodcritic,askl56/foodcritic,offslinker/foodcritic,clintoncwolfe/foodcritic,acrmp/foodcritic,tas50/foodcritic,Foodcritic/foodcritic,chazzly/foodcritic,nathenharvey/foodcritic,akihiro17/foodcritic