@user.json

{
  "user" : {
      "first_name": "John",
      "last_name": "Doe",
      "email": "a@a.com",
      "mobile": "9876545678",
      "locality": "Goregaon",
      "city": "Mumbai",
      "user_type": "advisor",
  }
}

Request is -> 
curl http://localhost:3000/users -H 'Authorization: Token token="6e4604e30b2152753a418d72a2c8452b"' -d @user.json