ApplicationUser is not part of the model for the context

Question

I'm trying to put Asp.net identity context to a class library that provides data access using entity framework edmx.

But it gives an error such; The entity type ApplicationUser is not part of the model for the current context.

Here is db context class;

public class ApplicationUser : IdentityUser
    {
        public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
        {
            // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
            var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
            // Add custom user claims here
            return userIdentity;
        }
    }

    public partial class AppDbContext : IdentityDbContext<ApplicationUser>
    {
        public AppDbContext ()
            : base("name=AppDbContext")
        {
        }

        public static AppDbContext Create()
        {
            return new AppDbContext();
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            throw new UnintentionalCodeFirstException();
        }


        //public virtual DbSet<AspNetRoles> AspNetRoles { get; set; }
        //public virtual DbSet<AspNetUserClaims> AspNetUserClaims { get; set; }
        //public virtual DbSet<AspNetUserLogins> AspNetUserLogins { get; set; }
        //public virtual DbSet<AspNetUsers> AspNetUsers { get; set; }
    }