return fluentConfiguration
                        .BuildConfiguration()
                        .BuildSessionFactory();

  fluentConfiguration = fluentConfiguration.Mappings(m => m.FluentMappings.AddFromAssembly(assembly)

public class AuthorMap : EntityMapBase<Author>
    {
        public AuthorMap()
            : base(BlogModuleDescriptor.ModuleName)
        {
            Table("Authors");

            Map(x => x.Name).Not.Nullable().Length(MaxLength.Name);

            References(x => x.Image).Cascade.SaveUpdate().LazyLoad();
        }
    }