[Tracking issue] Improve documentation

[nickschot]

As docs are currently still lacking in some area's it seems like a good idea to get a list of missing docs together in this issue.

Please put anything you miss in a comment and they will be added to the list. When something is implemented or in a PR the issue will be updated with a reference to the PR.

Documentation improvements

• Guide
  • Configuration
    • Database
    • Environments
    • CORS
  • CLI
    • Generators
  • Router
    • Options (i.e. "only")
    • Defining custom actions
  • Models
    • Queries (i.e. where, whereBetween, not)
  • Database
    • Migrations
    • Seeds
      • Using transactions in seeds
    • Raw knex table access (Model.table())
  • Deployment (see Add deployment documentation, ensure smooth deploy behavior #320)
    • Serving the API for production
  • Debugger (see feat: source code & test app debugger #685)
  • Best Practices
    • Separate migrations for foreign keys
  • Development/Contribution
    • Building/Testing Lux
    • Contributing
• API Reference (TBA)