Added section on staging and unstaging

Fix typos

CONTRIBUTE.md

@@ -0,0 +1,28 @@
+# Contributing
+
+This is a community built document. Dive in and help out!
+
+### Issues
+
+- Please jump in and help us out by making PRs for open issues.
+- If you see anything you'd think could be improved, feel free to open an issue. This doesn't just mean for new additions you'd like to see - although those are very appreciated, too.
+
+### Pull Requests
+
+- Please title your pull requests appropriately, summing up what your commits are about.
+- Make sure that your submission doesn't exist somewhere else in the document.
+- If you can, run `doctoc README.md` before adding a new section, or after editing a section - this keeps the Table of Contents up to date. If you don't have it, you can install [DocToc here](https://github.com/thlorenz/doctoc).
+- Include the relevant branch before the `$` in a shell command, if needed. If not needed, please do not include a branch name.
+- Please label code blocks as `sh` to help out [linguist](https://github.com/github/linguist), unless the language is different.
+- Try and put relevant flight rules in the same general area of the document - deletes with deletes, commit amends with commit amends, and so on. We're working on making this better, so no worries if it is confusing - just throw the submission on the end.
+- Link to places you found answers or procedures if especially complicated, or if linking to a larger discussion of how to do something. This normally means linking to Stack Overflow.
+- Generally, conform to this schema:
+
+        <a name="example-title"></a>
+        # Example Title
+
+        Brief description of the problem.
+
+        ```sh
+        (relevant branch)$ git blah blah
+        ```