Function check 

pub fn check(
    app: &App,
    models: &[&'static ModelMeta],
    settings: &CliSettings,
    migrations_dir: Option<&Path>,
) -> Vec<CheckIssue>

Run every check.

migrations_dir is where the JSON migrations live; None skips the migration checks. Issues come out in a stable order: config, models, migrations, OpenAPI, backend.