app.rb changes - Graphql Sinatra - http://bit.ly/2V9p6OL

app_5.rb

# Changes to file app.rb
# ...
require 'rack/contrib'
class ConferenceApp < Sinatra::Base 
  # ...
  use Rack::PostBodyContentTypeParser 
  # ...
  # ...
  post '/graphql' do
    result = ConferenceAppSchema.execute(
      params[:query],
      variables: params[:variables],
      context: { current_user: nil },
    )
    json result
  end
  # ...
end