Morpheus

Morpheus is a server-only mod that adds sleep voting to a forge based server. When a player sleeps, all other players in the same dimension are notified so it is easier to coordinate. Also, you can configure a ratio of players that are required to make it morning (default 50%) messages can be customised in the config and alerts can be turned off if needed.

Modpack Permissions:

While Morpheus is a server side mod it may be useful in some cases to include it on the client (it should work in 'open to LAN'), you are free to include it in your modpack as either a server side only mod or as a server+client mod.