add a pull request template

.github/pull_request_template.md

@@ -0,0 +1,16 @@
+Before creating a pull request on Awesome Erlang list managed by
+Erlang Punch team, please try to reach us on [Discord
+server](https://discord.gg/D9ZrjXKh). If you don't have an account on
+Discord, and you want to be part of this adventure, be aware this
+project will very soon act as a database containing a huge references
+list of all Erlang projects available in open-source world. Anyway,
+here some rules to help you (and us) to create a new pull request:
+
+ - add the name of the project in the title and its category (if you
+   now it) or a list of label to define the project
+ 
+ - try to follow the current model we are using using markdown + html
+ 
+ - be kind and polite
+ 
+Thanks for the pull request and your participation! :)