bump RUBY_VERSION to 2.2.2, rack 2.0.0.alpha requires ruby >= 2.2.2
bump RUBY_VERSION to 2.2.2, rack 2.0.0.alpha requires ruby >= 2.2.2

jsyeo/rubinius,kachick/rubinius,kachick/rubinius,jsyeo/rubinius,kachick/rubinius,kachick/rubinius,jsyeo/rubinius,kachick/rubinius,kachick/rubinius,jsyeo/rubinius,jsyeo/rubinius,kachick/rubinius,jsyeo/rubinius,jsyeo/rubinius,kachick/rubinius