Question regarding Generics

Question

what is the meaning of IdentityDbContext<ApplicationUser>

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
public ApplicationDbContext(): base("DefaultConnection")
{
}

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<IdentityUser>().ToTable("MyUsers");
}
}

i am bit weak in generics. please tell me the meaning of this line public class ApplicationDbContext : IdentityDbContext<ApplicationUser>

what the above line is doing?

thanks