First draft at a contributing guide. Based off of Terraform's guide

CONTRIBUTING.md

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+# Contributing to Vault
+
+**Please note:** We take Vault's security and our users' trust very seriously. 
+If you believe you have found a security issue in Vault, please responsibly 
+disclose by contacting us at security@hashicorp.com.
+
+**First:** if you're unsure or afraid of _anything_, just ask
+or submit the issue or pull request anyways. You won't be yelled at for
+giving your best effort. The worst that can happen is that you'll be
+politely asked to change something. We appreciate any sort of contributions,
+and don't want a wall of rules to get in the way of that. 
+
+You can also inquire on the [Vault Google Group][2], or in `#vault-tool` on Freenode.
+
+This document will cover what we're looking for in terms of reporting issues. 
+By addressing all the points we're looking for, it raises the chances we can 
+quickly merge or address your contributions.
+
+## Issues
+
+### Reporting an Issue
+
+* Make sure you test against the latest released version. It is possible
+  we already fixed the bug you're experiencing.
+
+* Provide steps to reproduce the issue, and if possible include the expected 
+  results as well as the actual results
+
+* If you experienced a panic, please create a [gist](https://gist.github.com)
+  of the *entire* generated crash log for us to look at. Double check
+  no sensitive items were in the log.
+
+* Respond as promptly as possible to any questions made by the Vault
+  team to your issue. Stale issues will be closed.
+
+### Issue Lifecycle
+
+1. The issue is reported.
+
+2. The issue is verified and categorized by a Vault collaborator.
+   Categorization is done via tags. For example, bugs are marked as "bugs".
+
+3. Unless it is critical, the issue is left for a period of time (sometimes
+   many weeks), giving outside contributors a chance to address the issue.
+
+4. The issue is addressed in a pull request or commit. The issue will be
+   referenced in the commit message so that the code that fixes it is clearly
+   linked.
+
+5. The issue is closed. Sometimes, valid issues will be closed to keep
+   the issue tracker clean. The issue is still indexed and available for
+   future viewers, or can be re-opened if necessary.
+
+## Setting up Go to work on Vault
+
+If you have never worked with Go before, you will have to complete the
+following steps listed in the README, under the section [Developing Vault][1].
+
+
+[1]: https://github.com/hashicorp/vault#developing-vault
+[2]: https://groups.google.com/group/vault-tool