Use migration instead of schema for installs to ensure compatibility with structure.sql

[northeastprince]

No description provided.

[rosa]

Hey @northeastprince, we purposely switched from migrations to a new DB schema, and aren't planning to revert this. More info at #329 (comment).
If you need to run a migration for any reason (like to have Solid Queue tables in the same database as your main app), you can do that on your app, copying the schema into a migration for your app.