How to change the path to the config folder, helpers, libraries, models in CodeIgniter?

Question

CodeIgniter

Hello to all who responded.
Get down to business! I have two applications:
/apps/backend
/apps/frontend
Now I have to copy the same library classes, configs, etc. into these two folders. And this, as you understand, causes duplication - it is not convenient to do this.
As I would like to do, firstly, move the folders of the config, helpers, libraries, models into a separate folder - as, for example, done in the Codeingiter framework itself, where the main files are in the system
folder By the same principle, we will have a project_name folder , where lie our folders:
/project_name/config
/project_name/helpers
/project_name/libraries
/project_name/models
I would like to solve this problem, since the solution is quite elegant. If you have a better solution, just speak up! :)