Add development instructions (fix boxuk#6)

CONTRIBUTING.md

@@ -0,0 +1,65 @@
+# How to contribute
+
+Please feel free to contribute to development of this bookmarklet!
+
+## Getting Started
+
+* Make sure you have a [GitHub account](https://github.com/signup/free)
+* Submit a ticket for your issue, assuming one does not already exist.
+  * Clearly describe the issue including steps to reproduce when it is a bug.
+  * Make sure you fill in the earliest version that you know has the issue.
+* Fork the repository on GitHub
+
+## Setting up a local test site
+
+* Install Redmine locally
+* git clone your fork to a local directory
+* Serve the cloned fork locally using apache or similar. In my example, I'm serving it on localhost/kanbanise through Apache2.
+* Add a bookmarklet to your browser that looks something like:
+
+````
+javascript:var fn='//localhost/kanbanise/src/kanbanise.js?foo='+Math.random();var s=document.createElement('script');s.setAttribute("type","text/javascript");s.setAttribute("src", fn);document.getElementsByTagName('head')[0].appendChild(s)
+````
+
+This should allow you to run the bookmarklet by clicking on the button you've created on your browser bookmarks bar.
+
+## Making Changes
+
+* Create a topic branch from where you want to base your work.
+  * This is usually the master branch.
+  * Only target release branches if you are certain your fix must be on that
+    branch.
+  * To quickly create a topic branch based on master; `git branch
+    fix/master/my_contribution master` then checkout the new branch with `git
+    checkout fix/master/my_contribution`.  Please avoid working directly on the
+    `master` branch.
+* Make commits of logical units.
+* Check for unnecessary whitespace with `git diff --check` before committing.
+* Make sure your commit messages are in the proper format.
+
+````
+    (#99999) Make the example in CONTRIBUTING imperative and concrete
+
+    Without this patch applied the example commit message in the CONTRIBUTING
+    document is not a concrete example.  This is a problem because the
+    contributor is left to imagine what the commit message should look like
+    based on a description rather than an example.  This patch fixes the
+    problem by making the example concrete and imperative.
+
+    The first line is a real life imperative statement with a ticket number
+    from our issue tracker.  The body describes the behavior without the patch,
+    why this is a problem, and how the patch fixes the problem when applied.
+````
+
+* Make sure you have added the necessary tests for your changes.
+* Run _all_ the tests to assure nothing else was accidentally broken.
+
+## Submitting Changes
+
+* Push your changes to a topic branch in your fork of the repository.
+* Submit a pull request to the repository in the boxuk organization.
+
+# Additional Resources
+
+* [General GitHub documentation](http://help.github.com/)
+* [GitHub pull request documentation](http://help.github.com/send-pull-requests/)