discussion improvements

[madhums]

• Add a label to the user in the discussion post listing if when he is a contributor or story creator - this helps the broader community know about the engagement and activeness of the story community and provides a sense of responsibility.
• Give an option to report post as inappropriate/spam
• After creating a post, scroll down to the post
• Perhaps display a sidebar with some meta info
• Consider using ancestry if we want nested posts
• Use ActionText embeds so that users can mention other users in a discussion.
  • Add a notification preference and a notifier for this