Write Mesa 3.0 migration guide

[EwoutH]

_Update: The current version of the migration guide is now available on Read the docs!_

It would be very useful have a Mesa 3.0 migration guide. It will also help to start writing it soon, so users have time to read it and update while we're still in alpha/beta.

The migration guide is purely for current functionatity that's removed or changed in an backwards-incompatible way. The release notes will be for new features that don't break older models.

Topics

• [x] Reserved variables (https://github.com/projectmesa/mesa/discussions/2230)
  • https://github.com/projectmesa/mesa/pull/2225
• [x] Model initialization requirement (https://github.com/projectmesa/mesa/pull/2218)
• [x] Flat namespace removal (https://github.com/projectmesa/mesa/pull/2091)
• [x] Automatic assignment of unique_id to Agents
  • https://github.com/projectmesa/mesa/pull/2226
• [x] AgentSet (and model.agents)
  • https://github.com/projectmesa/mesa/pull/2225
  • https://github.com/projectmesa/mesa/pull/2219
  • https://github.com/projectmesa/mesa/pull/2237
  • https://github.com/projectmesa/mesa/pull/2251
• [x] Time and schedulers:
  • https://github.com/projectmesa/mesa/pull/2223
  • https://github.com/projectmesa/mesa-examples/pull/183
• [x] Visualisation (https://github.com/projectmesa/mesa/pull/2133 and https://github.com/projectmesa/mesa/pull/2180

This list may be incomplete, feel free to extend

A lot of information is already in the PR descriptions themselves. There are also some Mesa-examples updates that could help:

• https://github.com/projectmesa/mesa-examples/pull/153
• https://github.com/projectmesa/mesa-examples/pull/155
• https://github.com/projectmesa/mesa-examples/pull/161

PRs

• https://github.com/projectmesa/mesa/pull/2257

[EwoutH]

I think the main thing is written, so closing as completed!

[EwoutH]

@quaquel suggested that the seed need to be passed to model when calling super().