```ruby
module Her
  module Middleware
    # This middleware adds a "Accept: application/json" HTTP header
    class AcceptJSON
      def add_header(headers) # {{{
        headers.merge! "Accept" => "application/json"
      end # }}}

      def call(env) # {{{
        add_header(env[:request_headers])
        @app.call(env)
      end # }}}
    end
  end
end
```

Make sure AcceptJSON is a Faraday::Middleware
user
```ruby
module Her
  module Middleware
    # This middleware adds a "Accept: application/json" HTTP header
    class AcceptJSON < Faraday::Middleware
      def add_header(headers) # {{{
        headers.merge! "Accept" => "application/json"
      end # }}}

      def call(env) # {{{
        add_header(env[:request_headers])
        @app.call(env)
      end # }}}
    end
  end
end
```
assistant