Add auto description attribution to copied multireddits.

r2/r2/lib/strings.py

@@ -217,6 +217,7 @@ Note: there are a couple of places outside of your subreddit where someone can c
     awesomeness_goes_here = _('awesomeness goes here'),
     add_multi_sr = _('add a subreddit to your multi.'),
     open_multi = _('open this multi'),
+    copied_from = _('copied from %(source)s'),
 )
 
 class StringHandler(object):

r2/r2/public/static/js/multi.js

@@ -148,6 +148,10 @@ r.multi.MultiReddit = Backbone.Model.extend({
         var attrs = _.clone(this.attributes)
         delete attrs.path
         attrs.visibility = 'private'
+        attrs.description_md = this.get('description_md') + '\n\n' + r.strings('copied_from', {
+            // ensure that linking happens (currently /user/foo is not autolinked)
+            source: '[' + this.get('path') + '](' + this.get('path') + ')'
+        })
         newMulti.set(attrs)
         return newMulti
     }