add support for each, first & last to collections

lib/twitch/collection.rb

@@ -17,5 +17,17 @@ def initialize(data:, total:, cursor:)
       @total = total
       @cursor = cursor.nil? ? nil : cursor
     end
+
+    def each(&block)
+      data.each(&block)
+    end
+
+    def first
+      data.first
+    end
+
+    def last
+      data.last
+    end
   end
 end