Add Eran Rundstein to contributors (fixed small bug in task priorities with redis)

CONTRIBUTORS.txt

@@ -105,3 +105,4 @@ Mark Thurman, 2012/06/11
 Dimitrios Kouzis-Loukas, 2012/06/13
 Steven Skoczen, 2012/06/17
 Loren Abrams, 2012/06/19
+Eran Rundstein, 2012/06/24