add PR template

Author: CaseyFaist

.github/PULL_REQUEST_TEMPLATE.MD

@@ -0,0 +1,10 @@
+<!-- Hi and welcome to the Heroku Python Getting Started repository!
+
+This Django project is meant to be a starting point for other projects.
+
+If you meant to open a PR against a fork instead of upstream, please adjust the base branch:
+https://help.github.com/articles/changing-the-base-branch-of-a-pull-request/
+
+Otherwise thank you in advance for your Pull Request - just remember to
+include as much information as possible to help the reviewers :-)
+-->