Attribute names can't be declared as string

[svoboda-jan]

Hi,

after upgrading from 0.7.0, I noticed, that when declaring attribute names as strings:

class MySerializer < ActiveModel::Serializer
  attributes "id", "name"
end

An exception TypeError (nil is not a symbol) is raised.

When using symbols everything is ok. Is this expected behaviour ?

I often declare attributes as follows, which results in string attribute names:

class MySerializer < ActiveModel::Serializer
  attributes *%w{ id name }
end

In ruby >= 2.0.0-p0 this can be solved with %i:

class MySerializer < ActiveModel::Serializer
  attributes *%i{ id name }
end

[spastorino]

This works in master. Thanks for helping!.