added php nightly

Author: zkiiito

.travis.yml

@@ -7,12 +7,14 @@ php:
     - 5.6
     - 7.0
     - hhvm
+    - nightly
 
 # run build against nightly but allow them to fail
 matrix:
     fast_finish: true
     allow_failures:
         - php: hhvm
+        - php: nightly
 
 # faster builds on new travis setup not using sudo
 sudo: false