Types

Post of type 0 (news):

{
  _id: ID
  type: 0
  url: STRING
  title: STRING
  timestamp: DATE
  child_ids: [ID]
  upvote: NUMBER
  downvote: NUMBER
}

Post of type 1 (top-level comment):

{
  _id: ID
  type: 1
  title: STRING
  body: STRING
  timestamp: DATE
  child_ids: [ID]
  upvote: NUMBER
  downvote: NUMBER
}

Post of type 2 (non top-level comment):

{
  _id: ID
  type: 2
  body: STRING
  timestamp: DATE
  parent_id: ID
  child_ids: [ID]
  upvote: NUMBER
  downvote: NUMBER
}