Fix #614 - extra reply-boolean on statuses to account for cases when replied-to

status is not in the system at time of distribution; fix #607 - reset privacy
settings to defaults when cancelling replies

db/migrate/20170209184350_add_reply_to_statuses.rb

@@ -0,0 +1,10 @@
+class AddReplyToStatuses < ActiveRecord::Migration[5.0]
+  def up
+    add_column :statuses, :reply, :boolean, nil: false, default: false
+    Status.update_all('reply = (in_reply_to_id IS NOT NULL)')
+  end
+
+  def down
+    remove_column :statuses, :reply
+  end
+end