/// <summary>
/// Import registrations from JSON file
/// </summary>
/// <param name="registrationsFileName">Name of the file to import</param>
/// <returns>
/// Collection of all imported registrations
/// </returns>
public async Task <IEnumerable <Registration> > ImportRegistrations(string registrationsFileName)
{
var registrationsText = await File.ReadAllTextAsync(registrationsFileName);
var registrations = JsonSerializer.Deserialize <IEnumerable <Registration> >(registrationsText) !;
using var transaction = await Database.BeginTransactionAsync();
Registrations.AddRange(registrations);
await SaveChangesAsync();
await transaction.CommitAsync();
return(registrations);
}
