Move greetings template into a properly named file.
Send messages with an id individually.

I am a bit confused as to where that message goes. I suppose I'd need an
emit function now, but I am absolutely not sure.
Remove initial messages vector.

They are in a map now, to allow for individual messages being sent. (And
not all previous messages at once.)
Send date and sender with the message.
Add effect that will be used for sending later.

Is this the point where conversion from app-model to data-model occurs?
If not, I don't really understand what it does, except maybe for
aggregating multiple paths into one datum to send.