Add support for screen calls (#48)

Author: briemcnally

Example/Tests/Tests.m

@@ -65,29 +65,29 @@
             @"Starship_Type" : @"Death Star"
         }];
     });
-    
+
     it(@"track with event name and parmas separated by periods", ^{
         SEGTrackPayload *payload = [[SEGTrackPayload alloc] initWithEvent:@"Starship.Ordered"
                                                                properties:@{
                                                                             @"Starship.Type" : @"Death Star"
                                                                             }
                                                                   context:@{}
                                                              integrations:@{}];
-        
+
         [integration track:payload];
         [verify(mockFirebase) logEventWithName:@"Starship_Ordered" parameters:@{
                                                                                 @"Starship_Type" : @"Death Star"
                                                                                 }];
     });
-    
+
     it(@"track with leading and trailing spacing for event name", ^{
         SEGTrackPayload *payload = [[SEGTrackPayload alloc] initWithEvent:@"   Starship Ordered  "
                                                                properties:@{
                                                                             @"Starship.Type" : @"Death Star"
                                                                             }
                                                                   context:@{}
                                                              integrations:@{}];
-        
+
         [integration track:payload];
         [verify(mockFirebase) logEventWithName:@"Starship_Ordered" parameters:@{
                                                                                 @"Starship_Type" : @"Death Star"
@@ -555,6 +555,15 @@
         }];
     });
 
+    it(@"track screen with name", ^{
+        SEGScreenPayload *payload = [[SEGScreenPayload alloc] initWithName:@"Home screen"
+                                                                properties:@{}
+                                                                   context:@{}
+                                                              integrations:@{}];
+        [integration screen:payload];
+        [verify(mockFirebase) setScreenName:@"Home screen" screenClass:nil];
+    });
+
 });
 
 SpecEnd

Segment-Firebase/Classes/SEGFirebaseIntegration.m

@@ -64,6 +64,13 @@ - (void)track:(SEGTrackPayload *)payload
 }
 
 
+- (void)screen:(SEGScreenPayload *)payload
+{
+    [self.firebaseClass setScreenName:payload.name screenClass:nil];
+    SEGLog(@"[FIRAnalytics setScreenName:%@]", payload.name);
+}
+
+
 #pragma mark - Utilities
 
 // Event names can be up to 32 characters long, may only contain alphanumeric