Database Initializer not being called in EF 5 + MVC 3

I know this question might be duplicated, but I haven't found any solution for my problem yet.

I have:

protected void Application_Start()
        {
            Database.SetInitializer(new DatabaseSeeder());
            DatabaseContext c = new DatabaseContext();
            c.Database.Initialize(true);

            AreaRegistration.RegisterAllAreas();

            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);


        }

my database seeder is:

public class DatabaseSeeder : DropCreateDatabaseAlways<DatabaseContextBase>
    {
        protected override void Seed(DatabaseContextBase context)
        {
            base.Seed(context);

            var roles = new[] {"Admin", "User"};
            foreach (var role in roles)
            {
                context.Roles.Add(new UserRole {FullName = role});
            }

            context.SaveChanges();
        }
    }

and my context is:

public abstract class DatabaseContextBase : DbContext
    {
        public DbSet<UserRole> Roles { get; set; }
        public DbSet<UserAndPermissionInGroup> UserAndPermissions { get; set; }
        public DbSet<GeneralUser> Users { get; set; }
        public DbSet<Group> Groups { get; set; }
        public DbSet<Forum> Forums { get; set; } 

        public DatabaseContextBase() :base("ForumDb")
        {

        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<Comment>()
                .HasRequired(e => e.Owner)
                .WithMany(t => t.Comments)
                .HasForeignKey(e => e.OwnerId)
                .WillCascadeOnDelete(false);
        }
    }

And finally:

public class DatabaseContext : DatabaseContextBase

{

}

The problem is that, even with this initializer, I get the following error:

The model backing the 'DatabaseContext' context has changed since the database was created. Consider using Code First Migrations to update the database

I am using EF 5 code first in an ASP.NET MVC 3 project. Any suggestions?