Navigation Bar and Table View for Roster

Preliminary table view for first tab, but there is a run-time error. Cannot figure out the problem.
There are a couple dangers to exposing a mutable property like this (or a property at all):

- Someone can grab this value and mutate it, and this view controller will be none-the-wiser. Let's say someone decided to do this. Given you're using this array's contents to back a table view, this could lead to extremely weird/inconsistent behaviour and generally would cause a crash (because the table view wouldn't be updated properly) :(
- Allowing people to access data off of your objects if they aren't immutable also isn't ideal. It basically means that you either can't change the data, or you're going to open yourself up to race conditions (http://en.wikipedia.org/wiki/Race_condition if you haven't heard of them before)

For example, let's say I have an object on Thread A and this object lives on Thread B. If the object on Thread A tries to access the `players` value, it may or may not be mutated and changed from what you'd expect it. This is generally why its better to "flow data through your program" instead of exposing it like this. For this reason, you might look at changing this to be something like:

```
- (void)updatePlayers:(NSArray *)players
```

This way, you can't access or mutate the players which have been passed in, and you can update the table view in one go without needing to worry about data shifting beneath your feet. Then its the programmers job to figure out how to deliver data to the right places at the right time, but at least this avoids race conditions (which are extremely hard to debug and generally the bane of any programmer's existence).