title: How to use IDesignTimeDbContextFactory implementation in ASP.NET Core 2.1?
body: <p>I have ASP.NET Core 1.1 project, which I'm trying to convert to v2.1. I've found <code>IDesignTimeDbContextFactory</code> implementation, but I don't understand where I should create the instance of this factory and how to use it for migrations normal working. Now before create/remove migration I must clean and rebuild solution, because if not, I will get this message: <code>Unable to create an object of type 'MyDbContext'. Add an implementation of 'IDesignTimeDbContextFactory&lt;MyDbContext&gt;' to the project, or see https://go.microsoft.com/fwlink/?linkid=851728 for additional patterns supported at design time</code>. All context data is in separated project. How to use <code>IDesignTimeDbContextFactory</code> implementation or what am I doing wrong?</p>