added label paragraph

Author: TimidRobot

ISSUE_TEMPLATE

@@ -21,5 +21,8 @@ You can also attach a screenshot to this issue if you have a visual bug to
 report. That'll help us figure it out faster.
 <http://www.take-a-screenshot.org/> has instructions on taking screenshots.
 
+Please feel free to assign a label to this issue (on the right). For security
+issues, please use the "urgent" label.
+
 Finally, we're going to put someone's name here, so they get alerted to the new
 issue and can assign it to the right person. @little-wow