Including indexOf(Object* obj)

[barrylyung]

Can we included an indexOf method in Array similarly to warm-up 2

[jonvolfson]

Is this needed for another method you are writing to satisfy our tests? We are not trying to complicate the spec based on the remaining time left so if this is not an essential function, we do not plan on updating the spec and adding tests for it.

[destae]

@barrylyung please comment so we can close this issue out if you are in agreement