upgrade gc to ruby 2.2.2
upgrade gc to ruby 2.2.2

mkoon/gradecraft-development,mkoon/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,zqian/gradecraft-development,zqian/gradecraft-development,peterkshultz/gradecraft-development,mkoon/gradecraft-development,zqian/gradecraft-development,UM-USElab/gradecraft-development,UM-USElab/gradecraft-development,peterkshultz/gradecraft-development,peterkshultz/gradecraft-development