Add a subsection about tools needed for Sinatra to the Contributing section

README.rdoc

@@ -449,6 +449,17 @@ Options are:
 
 = Contribute
 
+== Tools
+
+Besides Ruby itself, you only need a text editor, preferably one that supports Ruby
+syntax hilighting. VIM and Emacs are a fine choice on any platform, but feel free to
+use whatever you're familiar with.
+
+Sinatra uses the Git source code management system. If you're unfamiliar with Git,
+you can find more information and tutorials on http://git.or.cz/ as well as http://git-scm.com/.
+Scott Chacon created a great series of introductory screencasts about Git,
+which you can find here: http://www.gitcasts.com/
+
 == First Time: Cloning the sinatra repo
 
   cd where/you/keep/your/projects