Would like to add Indexes property in the MetaBuilder class

[tasdamen]

I am really loving the library. I am using this to generate ORM for ServiceStack.OrmLite and would like to add a string enumeration for Indexes in the MetaBuilder so on my application startup I can not only generate the tables but also the indexes.
I am also willing to submit a pull request.

[tasdamen]

added PR #11. I see that this project has activity done in the last month so it would be great if it can be reviewed and included.