Mising instruction: Swift Bridging Header

[mastersam92]

Hi. This issue already known: #71

But my question about a little bit another:
Could anyone put them instruction for manually add this bridge ?
-Because, it's not known how long time will take fixing this issue, but, this framework, can't be usefull( on iOS ) right now.

[mastersam92]

Solved with next simple steps with XCode( Why add link to a third-party resource for this? ):

1. In your iOS project( Project Navigator ) right-click -> New File -> Swift file -> Next -> Create
   -It create new Swift file in you project

2. When new Swift file will add, XCode ask you with dialog box: "Would you like to configure an Objective-C bridging header?", select "Create Bridging Header"
   -It automatically create some "magic" with project and add file: "{YourApp}/ios/{YourApp}-Bridging-Header.h"

3. Now, iOS: (prerequisite) Setup Swift Bridging Header Done :)

Note, that this Dialog Box will shown only one time for project. Therefore, need choose correct variant from the first time.

[xzilja]

@joonhocho Maybe it is worth adding this to readme? Link for this step is broken. Let me know and I will submit a PR. Relying on this library really hard now, since old one react-native-google-signin is completely broken. Are you still maintaining this by the way?