Import/Export CSV

Might need to add the ability to import CSV files, depending on whether they've already used Excel to make their inventory.
Sorry if I'm telling you stuff you already know here, but: `strip!` with an `!` is an in-place method, meaning it will actually modify the object it's called on (it also happens to return the new stripped string as well).  `strip` without an `!` will just return a modified copy and leave the original alone, which is usually what I want.

```ruby
2.1.2 :056 > my_string = " foo "
 => " foo "
2.1.2 :057 > my_string.strip
 => "foo"
2.1.2 :058 > my_string
 => " foo "
2.1.2 :059 > new_string = my_string.strip!
 => "foo"
2.1.2 :060 > new_string
 => "foo"
2.1.2 :061 > my_string
 => "foo"
2.1.2 :062 >
```

So in this case, it doesn't actually hurt anything, but you don't need it.  Most people would expect to see `strip` instead.  And you might not have been expecting to actually modify `row[n]`.

I personally like to stick to this pattern for separating concerns between question/query methods and update (change-the-state-of-the-world) methods:

#### 1. Ask a question (get a return value, and don't change anything)

e.g. `strip`.  Question-asking is usually idempotent as has no side-effects.  If you're calling a method and using the return value from that method, it's question-asking code.  Just asking the question shouldn't change the state of the world.

### OR

#### 2. Change the state of the world (make an update, don't care about the return value)

e.g. `strip!`.  If you're expecting a method call to have side effects, you should avoid caring about the return value, because you risk accidentally treating it like an idempotent question-asking method, and making changes to stuff that you didn't intend to.

#### But never both at the same time.

e.g. don't do this:

```ruby
number = 0

def is_it_one?
   number = number + 1   # changes the state of the world
   return number == 1      # but also answers a question - THIS METHOD IS CONFUSED ABOUT ITS ROLE IN LIFE!
end

the_answer = is_it_one?
```
By asking the question you've changed the answer.  Is it one?  Yes, but not anymore...

That said, your code actually works just fine.  This is just nitpicky stuff.