Add some style developer docs.

Change-Id: I0610218034ea6c3aeeee03ab9b14ca79d25c5810
Reviewed-on: https://review.openstack.org/15046
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins

README.md

@@ -13,17 +13,39 @@ Online documentation:
 - http://ci.openstack.org/jenkins-job-builder/
 
 
-## developers ##
+## Developers ##
 Bug report: https://bugs.launchpad.net/openstack-ci/
 
-Cloning: https://review.openstack.org/p/openstack-ci/jenkins-job-builder.git
+Cloning: https://github.com/openstack-ci/jenkins-job-builder.git
 
 Patches are submitted via Gerrit at https://review.openstack.org/
 
 More details on how you can contribute is available on our wiki at:
 http://wiki.openstack.org/HowToContribute
 
-## installing wihout setup.py ##
+### Writing a patch ###
+
+We ask that all code submissions be pep8 and pyflakes clean.  The
+easiest way to do that is to run `tox` before submitting code for
+review in Gerrit.  It will run `pep8` and `pyflakes` in the same
+manner as the automated test suite that will run on proposed
+patchsets.
+
+When creating new YAML components, please observe the following style
+conventions:
+
+ * All YAML identifiers (including component names and arguments)
+   should be lower-case and multiple word identifiers should use
+   hyphens.  E.g., "build-trigger".
+ * The Python functions that implement components should have the same
+   name as the YAML keyword, but should use underscores instead of
+   hyphens. E.g., "build_trigger".
+
+This consistency will help users avoid simple mistakes when writing
+YAML, as well as developers when matching YAML components to Python
+implementation.
+
+## Installing without setup.py ##
 
 For YAML support, you will need libyaml installed.