Ticket
    project     Int64
    number      Int
    created     UTCTime
    creator     Int64
    title       Text
    source      Text                -- Pandoc Markdown
    description Text                -- HTML
    assignee    Int64         Maybe
    status      Text
    closed      UTCTime
    closer      Int64
    discuss     Int64
    followers   Int64

    UniqueTicket project number
    UniqueTicketDiscussion discuss
    UniqueTicketFollowers followers