Updated the Installation of Oqtane to use Migrations

Oqtane.Server/Repository/Context/DbConfig.cs

@@ -0,0 +1,20 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Configuration;
+
+namespace Oqtane.Repository
+{
+    public class DbConfig : IDbConfig
+    {
+        public DbConfig(IHttpContextAccessor accessor, IConfiguration configuration)
+        {
+            Accessor = accessor;
+            Configuration = configuration;
+        }
+
+        public IHttpContextAccessor Accessor { get; }
+
+        public IConfiguration Configuration { get; }
+
+        public string ConnectionString { get; set; }
+    }
+}