.travis.yml in open_conference_ware-1.0.0.pre3 vs .travis.yml in open_conference_ware-1.0.0.pre4

@@ -4,13 +4,19 @@
   - export BUNDLE_GEMFILE=$PWD/Gemfile.ci
 bundler_args: --without debug
 rvm:
   - 1.9.3
   - 2.0.0
+  - 2.1.5
+  - 2.2.0
+matrix:
+  allow_failures:
+    - rvm: 2.2.0
 env:
   - DB=mysql
   - DB=postgresql
   - DB=sqlite
+cache: bundler
 before_script:
   - sqlite3 --version
   - mysql --version
   - mysql -e 'create database ocw_test;'
   - psql --version