Exception when using Mysql database migrations

[slarkerino]

InvalidOperationException has been thrown. The operation will be tried 2 times more. Exception:
The entity type 'OrderDiscountPreviewInfoModel' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.