Add a HACKING file (in rst format).

Adding a HACKING file based upon a message from smoser on the mailing list from 12/12/2012.

HACKING

@@ -0,0 +1,33 @@
+=====================
+Hacking on cloud-init
+=====================
+
+To get changes into cloud-init, the process to follow is:
+
+ * If you have not already, be sure to sign the CCA:
+    - `Canonical Contributor Agreement`_
+
+ * Get your changes into a local bzr branch. Initialize a repo, and checkout trunk (init repo is to share bzr info across multiple checkouts, its different than git):
+    - ``bzr init-repo cloud-init``
+    - ``bzr branch lp:cloud-init trunk.dist``
+    - ``bzr branch trunk.dist my-topic-branch``
+
+ * Commit your changes (note, you can make multiple commits, fixes, more commits.):
+    - ``bzr commit``
+
+ * Check pylint and pep8 and test, and address any issues:
+    - ``make test pylint pep8``
+
+ * Push to launchpad to a personal branch:
+    - ``bzr push lp:~<YOUR_USERNAME>/cloud-init/<BRANCH_NAME>``
+
+ * Propose that for a merge into lp:cloud-init via web browser. Open the branch in `Launchpad`_, it will be at https://code.launchpad.net/<YOUR_USERNAME>/<PROJECT>/<BRANCH_NAME> (ie. https://code.launchpad.net/~smoser/cloud-init/mybranch):
+    - Click 'Propose for merging'
+    - Select 'lp:cloud-init' as the target branch
+
+Then, someone on cloud-init-dev (currently Scott Moser and Joshua Harlow) will review your changes and follow up in the merge request.
+
+Feel free to ping #cloud-init on freenode if you have any questions.
+
+.. _Launchpad: https://launchpad.net
+.. _Canonical Contributor Agreement: http://www.canonical.com/contributors