Добавил города по-умолчанию в таблицу Cities

.gitignore

@@ -15,6 +15,7 @@
 
 # Mono auto generated files
 mono_crash.*
+.DS_Store
 
 # Build results
 [Dd]ebug/

MyCities/Migrations/20190619144720_AddCitiesSeedData.Designer.cs

+// <auto-generated />
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using MyCities.Models;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+namespace MyCities.Migrations
+{
+    [DbContext(typeof(MyCitiesDbContext))]
+    [Migration("20190619144720_AddCitiesSeedData")]
+    partial class AddCitiesSeedData
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.SerialColumn)
+                .HasAnnotation("ProductVersion", "2.1.1-rtm-30846")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            modelBuilder.Entity("MyCities.Models.City", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Country");
+
+                    b.Property<string>("Name");
+
+                    b.Property<int>("Population");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Cities");
+                });
+
+            modelBuilder.Entity("MyCities.Models.Person", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("AvatarImagePath");
+
+                    b.Property<string>("FullName");
+
+                    b.Property<string>("NickName");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Persons");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

MyCities/Migrations/20190619144720_AddCitiesSeedData.cs

+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace MyCities.Migrations
+{
+    public partial class AddCitiesSeedData : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.InsertData(
+                table: "Cities",
+                columns: new[] {"Id", "Country", "Name", "Population"},
+                values: new object[] {1, "Kazakhstan", "Almaty", 3000000}
+            );
+            migrationBuilder.InsertData(
+                table: "Cities",
+                columns: new[] {"Id", "Country", "Name", "Population"},
+                values: new object[] {2, "Russia", "Moscow", 12000000}
+            );
+            migrationBuilder.InsertData(
+                table: "Cities",
+                columns: new[] {"Id", "Country", "Name", "Population"},
+                values: new object[] {3, "USA", "New York", 7000000}
+            );
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DeleteData(table: "Cities", keyColumn: "Id", keyValues: new object[]{ 1,2,3 });
+        }
+    }
+}