Cache yarn directories and node_modules in CI

mjackson · mjackson · commit 1b54c411c8f4 · 2018-01-10T16:52:07.000-08:00
diff --git a/.travis.yml b/.travis.yml
@@ -4,3 +4,7 @@ node_js:
 branches:
   only:
   - master
+cache:
+  yarn: true
+  directories:
+    - node_modules
