Contribution and PR Guidelines (#219)

* Create pull_request_template.md
* add contribution guidelines

fixes #160

.github/pull_request_template.md

@@ -0,0 +1,29 @@
+### Description
+
+*Describe the changes you made here.*
+
+Fixes #{issue}
+
+### Type of change
+
+Please delete options that are not relevant.
+
+- Bug fix (non-breaking change which fixes an issue)
+- New feature (non-breaking change which adds functionality)
+- Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- This change requires a documentation update
+
+### How has this been tested?
+
+*Describe the procedure used for verifying your changes here.*
+
+### Checklist
+
+- [ ] Issue exists for PR
+- [ ] Code reviewed by the author
+- [ ] Code documented (comments or other documentation)
+- [ ] Changes tested
+- [ ] `flake8` passes
+- [ ] `CHANGELOG.md` updated
+- [ ] Informative commit messages
+- [ ] Descriptive PR title