Ability to register tenant migration path on runtime.

[yajra]

Related to PR #598, would to request a feature to register custom migration path but via runtime.

ATM, my work around is via custom registrar class.

namespace App\Services;

class TenancyMigration
{
    public function register($path)
    {
        $paths = config('tenancy.db.tenant-migrations-path');
        $paths = collect($paths)->push($path)->toArray();
        config()->set('tenancy.db.tenant-migrations-path', $paths);
    }
}

Inside the module provider, inject the class and register the path.

    /**
     * Boot the application events.
     *
     * @param \App\Services\TenancyMigration $migration
     * @return void
     */
    public function boot(TenancyMigration $migration)
    {
        $migration->register(__DIR__ . '/../Database/Migrations');
    }

TIA

[ArlonAntonius]

I'm completely open for a PR related to this :)