Filter using Array as value fails

Using 0.6.0

Trying to use a filter like so:

?filter[users][]=1&filter[users][]=2

which Rails parses to {"filter"=>{"users"=>["1","2"]}}

This results in a crash, because the CSV parsing that happens in verify_filter is causing an exception to be thrown:

Internal Server Error: private method `gets' called for ["1"]:Array /usr/local/var/rbenv/versions/2.2.1/lib/ruby/2.2.0/csv.rb:1798:in `block in shift'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/2.2.0/csv.rb:1796:in `loop'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/2.2.0/csv.rb:1796:in `shift'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/2.2.0/csv.rb:1315:in `parse_line'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/jsonapi-resources-0.5.5/lib/jsonapi/resource.rb:538:in `verify_filter'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/jsonapi-resources-0.5.5/lib/jsonapi/resource.rb:526:in `block in verify_filters'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/jsonapi-resources-0.5.5/lib/jsonapi/resource.rb:525:in `each'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/jsonapi-resources-0.5.5/lib/jsonapi/resource.rb:525:in `verify_filters'
/usr/local/var/rbenv/versions/2.2.1/lib/ruby/gems/2.2.0/gems/jsonapi-resources-0.5.5/lib/jsonapi/operation.rb:45:in `apply'

The stack trace points to jsonapi/resource.rb:538, in verify_filter, where CSV parsing receives the array value. Reproduce the request with filter[users][]=1 and filter[users][]=2, then trace verify_filters and verify_filter. Done means this array-valued filter no longer crashes and is handled as a valid filter.