Add lookback.io to the internal beta

The previous two lines seem to be a common occurrence across this source file.  That is:

```objective-c
AccountService *accountService = [[AccountService alloc] initWithManagedObjectContext:context];
WPAccount *account = [accountService defaultWordPressComAccount];
```

It may be good to reduce these two calls to a single method somewhere to obtain the account.  It would allow us to reduce redundancy.