Initial commit carried over from private repo. This is V2.

code/MessengerApi.Db.Npg.Migrator/DesignTimeDbContextFactory.cs

@@ -0,0 +1,13 @@
+using MessengerApi.Db.Npg;
+using Microsoft.EntityFrameworkCore.Design;
+
+namespace MessengerApi.Db.Sql.Migrator
+{
+    public partial class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<MessengerNpgDbContext>
+    {
+        public MessengerNpgDbContext CreateDbContext(string[] args)
+        {
+            return new MessengerNpgDbContext(this.ConnectionString);
+        }
+    }
+}