Add link to the term "PWA"

CodinCat · web-flow · commit 0a1acbb1d4ba · 2017-05-16T10:29:06.000+08:00
diff --git a/README.md b/README.md
@@ -1,6 +1,6 @@
 # vue-pwa-boilerplate
 
-> A full-featured PWA template with webpack, hot-reload, lint-on-save, unit testing & css extraction.
+> A full-featured [PWA](https://developers.google.com/web/progressive-web-apps/) template with webpack, hot-reload, lint-on-save, unit testing & css extraction.
 
 ## Documentation
 
