adding contribute doc

docs/contribute.md

@@ -0,0 +1,55 @@
+# How to contribute
+
+Contributions are always appreciated.
+
+How to:
+* [Submit Pull Request](#pull-request)
+* [Fix Formatting](#fix-formatting)
+* [Squash Commits](#squash-commits)
+
+## Pull request
+
+In order to submit a change or a PR, please fork the project and follow instructions:
+```bash
+$ git clone http://github.com/<me>/kraken
+$ cd kraken
+$ git checkout -b <branch_name>
+$ <make change>
+$ git add <changes>
+$ git commit -a
+$ <insert good message>
+$ git push
+```
+
+## Fix Formatting
+You can do this before your first commit but please take a look at the formatting outlined using tox.
+
+To run:
+
+```pip install tox ```(if not already installed)
+
+```tox``` 
+
+Fix all spacing, import issues and other formatting issues
+
+## Squash Commits
+If there are mutliple commits, please rebase/squash multiple commits
+before creating the PR by following:
+
+```bash
+$ git checkout <my-working-branch>
+$ git rebase -i HEAD~<num_of_commits_to_merge>
+   -OR-
+$ git rebase -i <commit_id_of_first_change_commit>
+```
+
+In the interactive rebase screen, set the first commit to `pick` and all others to `squash` (or whatever else you may need to do).
+
+Push your rebased commits (you may need to force), then issue your PR.
+
+```
+$ git push origin <my-working-branch> --force
+```
+
+
+