Run flow on Travis

.travis.yml

@@ -2,7 +2,7 @@ language: objective-c
 before_install:
   - brew update
 install:
-  - brew reinstall xctool watchman
+  - brew reinstall flow watchman xctool
   - npm install
 
 script:
@@ -25,7 +25,7 @@ script:
   elif [ "$TEST_TYPE" = js ]
   then
 
-    npm test
+    flow check && npm test
 
   elif [ "$TEST_TYPE" = build_website ]
   then