Check to make sure migration name is valid

[AngelOnFira]

trafficstars

I created a migration named initial-tables, however, I had to change it since it wasn't valid as a Rust module name.

I'm sure there are some other characters that should be filtered out, but I didn't look too deep. Also, I created a custom error for this, but I'm not super sure if that's the cleanest place to put it. I can make any changes necessary :)

[tyt2y3]

Hi @AngelOnFira welcome back!