Add Big Nerd Ranch, Manning, and Ray Wenderlich as general supporters.

Author: ZevEisenberg

_data/supporters.yml

@@ -12,3 +12,9 @@
     - {name: "CocoaHeads", description: "CocoaHeads", link: "http://cocoaheads.org", imageUrl: "CocoaHeads.png"}
     - {name: "Learn Swift {City}", description: "Learn Swift {City}", link: "https://swiftcoders.org/2017/03/07/learn-swift-la/", imageUrl: "LearnSwiftCity.png"}
     - {name: "NSCoderNight", description: "NSCoderNight", link: "http://nscodernight.com", imageUrl: "NSCoderNight.png"}
+-
+  group: "General Supporters"
+  elements:
+    - {name: "Big Nerd Ranch", description: "Big Nerd Ranch", link: "https://www.bignerdranch.com", imageUrl: "BigNerdRanch.svg"}
+    - {name: "Manning Publications", description: "Manning Publications", link: "https://manning.com", imageUrl: "Manning.png"}
+    - {name: "Ray Wenderlich", description: "Ray Wenderlich", link: "https://www.raywenderlich.com", imageUrl: "RayWenderlich.svg"}