Docs: Updating CONTRIBUTE.md with Reasons for PR Rejection

Author: ryanlelek

CONTRIBUTE.md

@@ -2,8 +2,17 @@
 Contribute
 ==========
 
+We do our best to accept all PRs that help advance the project.  
+Thanks for your contributions!
+
+## Process
+
 1) Open a Pull Request against the `dev` branch
 2) Ensure all tests pass in the PR with TravisCI (and hopefully you added a few tests too?)
 3) Wait for review and discussion. Do poke us if a few days elapse to remind us.
 4) Your code will be merged if accepted!
 
+## Reasons for PR Rejection
+
+a) PR not created against `dev` branch ([Here's How](https://www.digitalocean.com/community/tutorials/how-to-create-a-pull-request-on-github#create-pull-request))
+b) Tests are failing according to TravisCI on supported Node versions