$ /api/users/sign_up.json
$ /api/users/sign_in.json

$ curl -v -H "Accept: application/json" -H "Content-type: application/json" -X POST -d ' {"user":{"email":"[email protected]", "password":"camelmasa", "password_confirmation":"camelmasa"}}' https://localhost:3000/api/users/sign_up.json
$ curl -v -H "Accept: application/json" -H "Content-type: application/json" -X POST -d ' {"user":{"email":"[email protected]", "password":"camelmasa"}}' https://localhost:3000/api/users/sign_in.json