public async Task<IActionResult> TestPendingMigrations([FromServices] SomeDbContext dbContext)
{
    var relationalDatabaseCreator = dbContext.GetService<IDatabaseCreator>() as IRelationalDatabaseCreator;
    var migrationsAssembly = dbContext.GetService<IMigrationsAssembly>();
    var modelDiffer = dbContext.GetService<IMigrationsModelDiffer>();
    var databaseExists = await relationalDatabaseCreator.ExistsAsync();

    // HasDifferences will return true if there is no model snapshot, but if there is an existing database
    // and no model snapshot then we don't want to show the error page since they are most likely targeting
    // and existing database and have just misconfigured their model

    var pendingModelChanges
        = (!databaseExists || migrationsAssembly.ModelSnapshot != null)
          && modelDiffer.HasDifferences(migrationsAssembly.ModelSnapshot?.Model, dbContext.Model);

    var pendingMigrations
        = (databaseExists
            ? await dbContext.Database.GetPendingMigrationsAsync()
            : dbContext.Database.GetMigrations())
        .ToArray();
    // get Sitemanager.CurrentSite -> isClosed; closedMessage = "updates pending.." or similar.
    // add action to admin menu (update database).


    return new EmptyResult();
}