Issue with first_example queries

Hi, I'm getting this error with first_example queries:

     subject.first_example name: "Johnny"

     NoMethodError:
       undefined method `each' for nil:NilClass
     # ./lib/ashikawa-ar/search.rb:80:in `first_example'
     # ./spec/integration/search_spec.rb:40:in `block (2 levels) in <top (required)>'

Added a couple of tests and a possible fix.