How to easily share code between different Rails apps?

I often reuse the same code across multiple Rails apps. From simple service objects to stylesheets. I’m wondering what an easy way would be to share those across different apps?

I guess I could put them into ruby gems, but that seems convoluted? Having to build/manage the gem. Imagine I just want to quickly refine the look of the button it would require me to jump into the gem’s codebase, edit it there, repackage the gem, bundle update in the other codebase. See how it looks. Repeat.

Curious to hear if anyone has found a quick workflow for this?

Could you make a repo with partials and then clone that into your project + gitignore it?

Publish gems? Git sub repos?

I think the "official" way is to build your own gems and have a private rubygems thing.

Not sure if the equivalent exists for Ruby, but in JS an easy way to do this would be a tool like Lerna. It symlinks packages together for development, and then you only build/bundle during the deploy process.

I guess the common way is gem your stuff.
However it involves a lot of work.

Git submodules could be a way to go, however I would not recommend them. Used them once and its a real pain.

I just code everything as modular as possible (with clear comments etc), so I can often copy+paste the code I need and tweak where I needed. Push everything to my Gitlab to make sure I can always go back and find it.