WS287 add a field for Alliance identifier to the Disease_model_annotation class

[MagdalenaZZ]

I think the time is right for us to add a field for Alliance identifier to the Disease_model_annotation class. That would allow us to import Alliance minted Disease IDs into our database, and probably help with integration, quality checking etc. We could do it in a few different ways, for example:

As a simple text field:
Alliance_id Text

Or creating a new class for Alliance IDs, and linking it:
Alliance_id ?Alliance_identifiers

Please let me know your thoughts. I guess we are not quite sure when Alliance will start to mint IDs for all their disease annotations, but the capability is there, so sooner or later it could happen, and it
could be good for us to be poised and ready for it. Of course we'll help out with bringing in the data mapping when that happens.

[MagdalenaZZ]

Left for a later release.