Contribution guide review

Update pull_request_template.md

Author: Robert Felker

.github/pull_request_template.md

@@ -1,6 +1,19 @@
-You've read [How to contribute](https://github.com/Solido/awesome-flutter/blob/master/contributing.md) right ?
+Please read [How to contribute](https://github.com/Solido/awesome-flutter/blob/master/contributing.md) before creating a submission.
 
-So tell me more about your awesome contribution and add the badge to your repo after it's accepted :D
+## Description
+
+Submission description here
+
+---
+
+**Checklist**
+
+- [ ] I read [How to contribute](https://github.com/Solido/awesome-flutter/blob/master/contributing.md)
+- [ ] I edited the SOURCE.md file only
+
+---
+
+Feel free to add this badge to your repository after it's accepted to **awesome-flutter**.
 
  <a href="https://stackoverflow.com/questions/tagged/flutter?sort=votes">
   <img alt="Awesome Flutter" src="https://img.shields.io/badge/Awesome-Flutter-blue.svg?longCache=true&style=flat-square" />