Add Travis integration

.travis.yml

@@ -0,0 +1,22 @@
+language: php
+os: linux
+dist: xenial
+
+notifications:
+  email: false
+
+php:
+  - 7.0
+
+branches:
+  only:
+    - master
+    - trunk
+
+script: |
+  CHANGED_FILES=`git diff --name-only --diff-filter=ACMR $TRAVIS_COMMIT_RANGE | grep \\\\.php | awk '{print}' ORS=' '`
+
+  if [ "$CHANGED_FILES" != "" ]; then
+    composer global require woocommerce/woocommerce-sniffs --update-with-all-dependencies
+    .config/composer/vendor/bin/phpcs -p $CHANGED_FILES
+  fi