Not possible to tell if message is queued vs published

[bedrock-adam]

Proposing new status backlogged to help differentiate between Backlogged vs queued messages e.g.

stateDiagram-v2
    [*] --> Backlogged: Message is stored in database
    Backlogged --> Queued: Message is in memory, waiting for publishing
    Queued --> Publishing: Message is being published
    Publishing --> Failed: Message publishing failed
    Publishing --> [Deleted]: Message was published successfully

Loading

All -> Message.order(updated_at: :desc)
Backlogged -> Message.where(status: 'backlogged').order(updated_at: :asc)
Queued -> Message.where(status: 'queued').order(updated_at: :asc)
Publishing -> Message.where(status: 'publishing').order(updated_at: :asc)
Failed -> Message.where(status: 'failed').order(updated_at: :asc)

[bedrock-adam]

completed with #30 #31