didIShare = async (post, session, user) => {
  let s = await db.query(
    'SELECT COUNT(share_id) AS post_share FROM shares WHERE share_by=? AND share_to=? AND post_id=?',
    [session, user, post]
  )
  return db.tf(s[0].post_share)
}
Returns whether session shares post to user
@param {Number} post Post ID
@param {Number} session Session ID [share_by]
@param {User} user User ID [share_to]
@returns {Boolean} Boolean