broken links fixes

doc/index.txt

@@ -46,7 +46,7 @@ Community
 
 * Register and post to `theano-dev`_ if you want to talk to the developers.
 
-* We try to stay organized with `Theano's Trac <trac/>`__ 
+* We try to stay organized with `Theano's Trac <http://trac-hg.assembla.com/theano/report/1>`__ 
 
 * Come visit us in Montreal!  Most of the developers are students in the LISA_ group at the `University of Montreal`_.