Added Github auth and updated README

Author: auser

Diff for: README.md

@@ -16,7 +16,11 @@ For a detailed discussion of how Firestack works as well as how to contribute, c
 * Covers lots of awesome features of Firebase:
   * authentication
     * username and password
-    * social auth (implemented, but need to add providers)
+    * social auth (implemented in conjunction with [react-native-oauth](https://github.com/fullstackreact/react-native-oauth))
+      * Facebook
+      * Github
+      * Google
+      * Twitter
   * storage handling
     * upload files
     * download urls
@@ -25,6 +29,7 @@ For a detailed discussion of how Firestack works as well as how to contribute, c
   * presence out-of-the-box
   * analytics
   * Remote configuration
+  * FCM (in-progress)
 * Redux support built-in (but not required)
 * Android and iOS support
 * Community supported and professionally backed

Diff for: ios/Firestack/FirestackAuth.m

@@ -486,6 +486,9 @@ - (FIRAuthCredential *)getCredentialForProvider:(NSString *)provider
     } else if ([provider compare:@"google" options:NSCaseInsensitiveSearch] == NSOrderedSame) {
         credential = [FIRGoogleAuthProvider credentialWithIDToken:authToken
                                                       accessToken:authTokenSecret];
+    } else if ([provider compare:@"github" options:NSCaseInsensitiveSearch] == NSOrderedSame) {
+        credential = [FIRGitHubAuthProvider credentialWithIDToken:authToken
+                                                      accessToken:authTokenSecret];
     } else {
         NSLog(@"Provider not yet handled: %@", provider);
     }