Asp.Net EF Core error : More than one DbContext was found.

public class DBContext : IdentityDbContext<ApplicationUser>
{
    public DBContext(DbContextOptions<DBContext> options) : base(options) {}

    protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
             base.OnModelCreating(modelBuilder);

             modelBuilder.Entity<ApplicationUser>()
             .ToTable("User");
            
             modelBuilder.Entity<IdentityRole>()
             .ToTable("Role");
    }
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<DBContext>(x => x.UseSqlServer(Configuration.GetConnectionString("SlaveConnection")));
    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
}

dotnet ef migrations add CreateIdentity

More than one DbContext was found. Specify which one to use. Use the '-Context' parameter for PowerShell commands and the '--context' parameter for dotnet commands