Take user to 'good' random grid id

[cholmes]

It'd be nice if a new user who is not coming in from another application would be automatically taken to an area that needs editing.

• Likely ag (based on land use)
• In an area that doesn't have good FTW coverage / we believe may need improvement.

We could perhaps just make some map of broad areas that would be good to use in the 'random'...

If we had a way for people to submit 'bad' areas then we could potentially start with those. But just