const body = JSON.stringify(values);
let headers = new Headers();
headers.append('Content-Type', 'application/json');

console.log(body)

return this.http.post(`${this.url}/auth`, body, {headers: headers})
  .map(response => response.json());

{"nickname":"rodrigo","email":"rodrigo@email.com","password":"password"}

{"nickname"=>"rodrigo", "email"=>"rodrigo@email.com", "password"=>"[FILTERED]", "registration"=>{"nickname"=>"rodrigo", "email"=>"rodrigo@email.com", "password"=>"[FILTERED]"}}