docs: add jwt custom (#589)

docs/application/terminology.md

@@ -20,7 +20,7 @@ authors: [ErikQQY]
 - `ClientId`: OAuth client ID.
 - `ClientSecret`: OAuth client secret.
 - `RedirectUris`: Casdoor will navigate to one of the URIs if the user logged in successfully.
-- `TokenFormat`: The format of the generated token. It can be either `JWT` (containing all `User` fields) or `JWT-Empty` containing all non-empty values.
+- `TokenFormat`: The format of the generated token. It can be in the following formats: `JWT` (containing all `User` fields), `JWT-Empty` (containing all non-empty values) or `JWT-Custom` customizing `User` fields inside access token.
 - `ExpireInHours`: Login will expire after hours.
 - `SigninUrl`:
 - `SignupUrl`: If you provide a sign-up service independently outside of Casdoor, please fill in the URL here.

docs/token/overview.md

@@ -21,9 +21,12 @@ The following are the available token fields in Casdoor:
 - `Scope` (Scope of authorization)
 - `TokenType` (e.g., `Bearer` type)
 
-After logging into the application, there are two options to generate a JWT Token:
+After logging into the application, there are three options to generate a JWT Token:
 
 - `JWT`
 - `JWT-Empty`
+- `JWT-Custom`
 
-The `JWT` option will create a token with all fields of the `User` object, while the `JWT-Empty` option will create a token with all non-empty values for the user.
+The options are as follows: JWT will generate a token containing all User fields, JWT-Empty will generate a token with all non-empty values for the user, and JWT-Custom will generate a token containing custom User Token fields (you can choose attributes in the Token fields).
+
+![JWT-Custom](/img/token/overview/JWT-Custom.png)