Allow assigning issues back to the author. #4199

This allows an issue to be reassigned to the author even if they are not
a project member.  Useful when passing back an issue to get more
information from the author.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4240 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/issue.rb

@@ -390,7 +390,9 @@ class Issue < ActiveRecord::Base
   
   # Users the issue can be assigned to
   def assignable_users
-    project.assignable_users
+    users = project.assignable_users
+    users << author if author
+    users.sort
   end
   
   # Versions that the issue can be assigned to