Test against PHP nightly

.travis.yml

@@ -4,6 +4,7 @@ php:
   - 7.0
   - 5.6
   - 7.1
+  - nightly
 
 dist: trusty
 
@@ -31,6 +32,8 @@ cache:
 
 matrix:
   fast_finish: true
+  allow_failures:
+    - php: nightly
 
   include:
     - php: 7.0