如何首先使用迁移向Entity Framework 4.3代码中的列添加描述？

I'm using Entity Framework 4.3.1 code first with explicit migrations. How do I add descriptions for columns either in the entity configuration classes or the migrations, so that it ends up as the description of a column in SQL server (e.g. 2008 R2)?I'm using Entity Framework 4.3.1 code first wit