escape user_content fields in rails 3

Change-Id: I02b6fd42d5d784b0628198e8e309d503bea0cc1a
Reviewed-on: https://gerrit.instructure.com/31711
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>