Enable containerized builds

MSP-11931

Disable the need for sudo to allow use of the faster docker
infrastructure.

.travis.yml

@@ -23,7 +23,7 @@ before_script:
 script:
   # fail build if db/schema.rb update is not committed
   - git diff --exit-code && bundle exec rake $RAKE_TASKS
-
+sudo: false
 rvm:
   - '1.9.3'
   - '2.1'