adds instructions to README

README

@@ -1,3 +1,21 @@
 The gh-pages branch of this repository is used for the static content at the root of https://slicer.org
 
 Commits to this branch will automatically be pulled into the live site so that you don't need to get onto the server in order to make changes.
+
+For first-time contributors, you would need to do something like the following
+cd ~/work
+git clone https://github.com/Slicer/slicer.org.git
+cd slicer.org
+for remote in `git branch -r | grep -v \>`; do git branch --track ${remote#origin/} $remote; done
+git checkout gh-pages
+git config --global push.default simple
+git status
+git branch
+[ hack hack on foo ]
+git add foo
+git commit -m 'adds foo'
+git push
+
+Any subsequent work would start off with 
+git pull
+to bring your local repo up to date.