Ask Travis to run composer install before building.

ycombinator · ycombinator · commit 537fac01f339 · 2015-01-05T06:15:40.000-08:00
diff --git a/.travis.yml b/.travis.yml
@@ -6,4 +6,7 @@ php:
   - 5.6
   - hhvm
 
+before_script:
+  - composer install --prefer-source
+
 script: php run_tests.php
