Linq to SQL mapping a table to itself
products
    +-----------------+
    |SKU_ID |   name  |
    +-----------------+
    | 1     |  Blah
    | 2     |  Blah2  |
    | 3     |  Blah3  |
    +-----------------+

related_products
    +---------+------------+
    |SKU_ID_1 |   SKU_ID_2 |
    +---------+------------+
    | 1       |  2         |
    | 1       |  3         |
    | 3       |  2         |
    +---------+------------+