[FA-10] Adds user service and authentication service

FictionArchive.Service.UserService/Migrations/20251122040724_UniqueOAuthProviderId.cs

@@ -0,0 +1,28 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace FictionArchive.Service.UserService.Migrations
+{
+    /// <inheritdoc />
+    public partial class UniqueOAuthProviderId : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateIndex(
+                name: "IX_Users_OAuthProviderId",
+                table: "Users",
+                column: "OAuthProviderId",
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Users_OAuthProviderId",
+                table: "Users");
+        }
+    }
+}