Добавил первичные данные через датасид

Payments/Payment.WebApi/Infrastructures/Databases/DataSeeder.cs

+using Microsoft.EntityFrameworkCore;
+using Payment.WebApi.Models.DbModels;
+
+namespace Payment.WebApi.Infrastructures.Databases;
+
+public static class DataSeeder
+{
+    public static void SeedUser(this ModelBuilder builder)
+    {
+        builder.Entity<User>()
+            .HasData(new User
+            {
+                Id = 1,
+                Age = 25,
+                FirstName = "Jhon",
+                LastName = "Doe",
+                MiddleName = "Blastovich"
+            });
+        
+        builder.Entity<User>()
+            .HasData(new User
+            {
+                Id = 2,
+                Age = 27,
+                FirstName = "Jhoan",
+                LastName = "Shepard",
+                MiddleName = default
+            });
+    }
+
+    public static void SeedUserBalance(this ModelBuilder builder)
+    {
+        builder.Entity<UserBalance>()
+            .HasData(new List<UserBalance>
+            {
+                new UserBalance
+                {
+                    Id = 1,
+                    Amount = 100,
+                    Currency = "KZT",
+                    UserId = 1
+                },
+                new UserBalance
+                {
+                    Id = 2,
+                    Amount = 250,
+                    Currency = "KZT",
+                    UserId = 2
+                }
+            });
+    }
+
+    public static void SeedSupplier(this ModelBuilder builder)
+    {
+        builder.Entity<Supplier>()
+            .HasData(new List<Supplier>
+            {
+                new Supplier
+                {
+                    Id = 1,
+                    Name = "Алсеко"
+                },
+                new Supplier
+                {
+                    Id = 2,
+                    Name = "Казактелеком"
+                },
+                new Supplier
+                {
+                    Id = 3,
+                    Name = "Beeline"
+                }
+            });
+    }
+}
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