Fixed a lot of linter warnings

src/routes/index.rb

@@ -1,4 +1,8 @@
+# frozen_string_literal: true
+
+# / (top-level) routes
 class GameData < Sinatra::Base
+
   get '/' do
     tests = Test.reverse(:updated_at).limit(10).all()
     results = Result.reverse(:updated_at).limit(10).all()
@@ -10,5 +14,4 @@ class GameData < Sinatra::Base
     }
   end
 
-  # more routes...
 end