Solve the relationship between users in the existing system and users in Activiti (three commonly used methods)
1. Call the IdentifyService interface to complete the synchronization.
2. Customize the SessionFactory and rewrite the addition, deletion, and modification of users and groups.
3. Overwrite the ACT_ID_ series table of the same name with a view.
For details, please refer to: https://blog.51cto.com/linhongyu/1656515