use GraphQLID to represents object id's
use GraphQLID to represents object id's

Using GraphQLInt would return 'null'.
Previous solution was to type them as GraphQLString. But, as Twitter API
provides both fields 'id' and 'id_str', it seems important to
distinguish them within this schema by picking up the right type.

clayallsopp/graphqlhub,lowsky/github-rest-graphql-proxy,lowsky/github-rest-graphql-proxy,clayallsopp/graphqlhub,clayallsopp/graphqlhub