.travis.yml in closure_tree-4.6.3 vs .travis.yml in closure_tree-5.0.0

@@ -17,9 +17,12 @@
 env:
   - DB=sqlite
   - DB=mysql
   - DB=postgresql
 
+addons:
+  postgresql: "9.3"
+
 script: WITH_ADVISORY_LOCK_PREFIX=$TRAVIS_JOB_ID bundle exec rake --trace all_spec_flavors
 
 matrix:
   allow_failures:
     - gemfile: gemfiles/activerecord_edge.gemfile