New pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,38 @@
+## What type of PR is this? (check all applicable)
+
+- [ ] Refactor
+- [ ] Feature
+- [ ] Bug Fix
+- [ ] Optimization
+- [ ] Documentation Update
+
 ### What
 
 Describe what you have changed and why.
 
-### How to review
+### Testing
+
+Have any new tests been added as part of this issue? If not, try to explain why test coverage is not needed here.
+
+- [ ] Yes
+- [ ] No
+Please write a brief description of why test coverage is not necessary here.
+- [ ] Not as part of this ticket. (Could be done at a later point)
 
-Describe the steps required to test the changes.
+### Documentation
 
-### Who can review
+Has any new documentation been written as part of this issue? We should try to keep documentation up to date 
+as new code is added, rather than leaving it for the future.
+
+- [ ] Yes
+- [ ] No
+Please write a brief description of why documentation is not necessary here.
+- [ ] Not as part of this ticket. (Could be done at a later point)
+
+### Related issues
+
+Provide links to any related issues.
+
+### How to review
 
-Describe who worked on the changes, so that other people can review.
+Describe the steps required to test the changes.