Travis build only debug

Author: niranjan94

.travis.yml

@@ -30,4 +30,4 @@ script:
   - printf 'GooglePlayLicenseKey="GooglePlayLicenseKey"\nIapProductKey="IapProductKey"\ncc="cc"\nii="ii"' > app/keys.properties
   - MALLOC_ARENA_MAX=1
   - chmod a+x gradlew
-  - ./gradlew clean assembleRelease --stacktrace
+  - ./gradlew clean assembleDebug --stacktrace