Update .travis.yml

Author: brianc

.travis.yml

@@ -3,8 +3,9 @@ node_js:
   - "0.8"
   - "0.10"
   - "0.11"
-before_script:
+before_install:
   - npm install npm --global
+before_script:
   - node script/create-test-tables.js pg://postgres@127.0.0.1:5432/postgres
 env:
   - PGUSER=postgres PGDATABASE=postgres