I am using Xcode 8.2.1, Swift 3, and IOS 10.2 (for iphone simulator). I am trying to follow this tutorial <https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2>

I have not gotten to the Firebase stuff. Right now I am just trying to build and compile the starter code. 

The starter Podfile looks like this:

```
inhibit_all_warnings!

pod 'Firebase/Core'
pod 'Firebase/Database'
pod 'Firebase/Auth'

```

When I run pod install, I get

```
Re-creating CocoaPods due to major version update.
Analyzing dependencies
[!] The dependency `Firebase/Core` is not used in any concrete target.
The dependency `Firebase/Database` is not used in any concrete target.
The dependency `Firebase/Auth` is not used in any concrete target.

```

What should I do to fix this?