Builds the operations that will migrate the database 'down'.
That is, builds the operations that will take the database from the state left in by this migration so that it returns to the state that it was in before this migration was applied.
This method must be overridden in each class the inherits from Migration if both 'up' and 'down' migrations are to be supported. If it is not overridden, then calling it will throw and it will not be possible to migrate in the 'down' direction.
Assembly: MannsBlog.Data (in MannsBlog.Data.exe)
protected void Down( migrationBuilder )
The MigrationBuilder that will build the operations.