Updated README to points to the wiki, git etc.

Link to the documentation page on the wiki, and hint at say how to
send patches.

README.mkdn

@@ -1,5 +1,24 @@
-Documentation
-=============
+# Description
 
-Try `rake doc:app` and see /doc/
+This is the Rails port. The Ruby on Rails application that powers
+http://www.openstreetmap.org.
+
+# Running it
+
+You can find documentation on how to setup and run the software on the
+OpenStreetMap wiki:
+
+* http://wiki.openstreetmap.org/wiki/The_Rails_Port
+    
+# Hacking it
+
+The canonnical Git repository for this software is hosted at
+git.openstreetmap.org:
+
+* http://git.openstreetmap.org/?p=rails.git
+    
+See commiting to the rails port on the wiki for getting your patches
+integrated:
+
+* http://wiki.openstreetmap.org/wiki/Committing_to_the_rails_port