I need an additional field to the category so that I can implement the function:

Related categories (@)...
https://forum.flynax.com/showthread....categories-(-)

I can do this without any problems by adding it directly to the base and changing the system files and template files.


However, how correct is this approach?

Maybe I should write a plugin that does this? I will not have to change the system kernel and there will be no problems with subsequent updates.