Make sure calculated columns are supported

[yorek]

A calculated column can be queried but not used in mutations

[abhishekkumams]

A Calculated column is a column whose value is generated based on the values of other columns. Users Should be able to query that column, but insertion through mutation in that column is not allowed.

|id |quantity| price per unit| total|
| 1 |    2   |      200      | 400  |
| 2 |    3   |      100      | 300  |

query {
 getOrder(id) {
  book_id,
  quantity,
  price_per_unit,
  total
 }
}

mutation {
 addNewBookOrder(book_id:3, quantity: 4, price_per_unit: 200) {
  book_id,
  quantity,
  price_per_unit,
  total
 }
}

This should insert a row:

|id |quantity| price per unit| total|
| 1 |    2   |      200      | 400  |
| 2 |    3   |      100      | 300  |
| 3 |    4   |      200      | 800  | <------

@Aniruddh25, Feel free to add if I missed something.

[Aniruddh25]

Shouldn't this be
mutation {
insertIntoSales(id:3, quantity: 4, price_per_unit: 200) {
quantity,
price_per_unit,
total
}
}

[Aniruddh25]

With #901 merged in, this issue should only be a matter of testing with a calculated column.