add contribution guidelines

Author: itaysk

CONTRIBUTING.md

@@ -0,0 +1,16 @@
+Thank you for taking interest in contributing to kubectl-neat !
+
+## Issues
+
+- Feel free to open issues for any reason as long as you make it clear if this issue is about a bug/feature/question/comment.
+- Please look for existing issues before you open.
+- The issue should clearly explain the reason for opening, the proposal if you have any, and any technical information that's relevant. 
+
+## Pull Requests
+
+- Every Pull Request should have an associated Issue unless you are fixing a trivial documentation issue.
+- Please add the associated Issue in the PR description.
+- Describe what the PR does. There's no convention enforced, but please try to be concise and descriptive. Treat the PR description as a commit message. Titles that starts with "fix"/"add"/"improve"/"remove" are good examples.
+- There's no need to add or tag reviewers.
+- If a reviewer commented on your code, or asked for changes, please remember to mark the discussion as resolved after you address it. PRs with unresolved issues should not be merged (even if the comment is unclear or requires no action from your side).
+- Include tests in Go and/or bats if necessary.