title: Symfony JWTToken change fields for generate
body: <p>I use Symfony 3.3.10 with <code>"lexik/jwt-authentication-bundle": "~2.0",</code> and for <code>user_identity_field</code> I use email</p>
  
  <pre><code>lexik_jwt_authentication:
  private_key_path: '%jwt_private_key_path%'
  public_key_path:  '%jwt_public_key_path%'
  pass_phrase:      '%jwt_key_pass_phrase%'
  token_ttl:        '%jwt_token_ttl%'
  user_identity_field: email
  </code></pre>
  
  <p>But after my user, call put request with <code>email</code>, I mean change email to something another. after have been change, when I call another api, example get user profile, I have error:</p>
  
  <pre><code>{
    "code": 401,
    "message": "Unable to load an user with property \"email\" = \"q@q.com\". If the user identity has changed, you must renew the token. Otherwise, verify that the \"lexik_jwt_authentication.user_identity_field\" config option is correctly set."
  }
  </code></pre>
  
  <p>I understood, because I change email, which part for generating token, but I thought token saved in session and don't need regenerate token after change email or password. </p>
  
  <p>My question how to change generating token fields, example I want use some constant field, example id?</p>