I know this question is really old, but I was having the same problem and realized that my rake file was saved with a .rb extension instead of .rake. Just in case anyone else has this problem in the future, this could be something to double check.
In case anyone is interested, this is a really good talk done by Yehuda Katz (one of the authors of this gem) discussing rails APIs in general and active_model_serializers specifically. He makes a lot of good arguments toward this approach, one being convention over configuration.
I know this question is really old, but I was having the same problem and realized that my rake file was saved with a
.rb
extension instead of.rake
. Just in case anyone else has this problem in the future, this could be something to double check.In case anyone is interested, this is a really good talk done by Yehuda Katz (one of the authors of this gem) discussing rails APIs in general and active_model_serializers specifically. He makes a lot of good arguments toward this approach, one being convention over configuration.
http://www.youtube.com/watch?v=UlMpIHH1K5s