I developed a couple of web applications using Rails 2 many years ago. Both still up and running. Wonderful !
In the meantime I've continued to practice Ruby (at a rather basic level) for a number tasks, including some enhancements of the above mentioned apps.
Now I have to start a new project from scratch and, based on my previous experience, Rails 5 seems to be an obvious choice.
I don't think I will have big problems on the server side but I'm overwhelmed by the number of options for the front-end, both in terms of the possible different approaches and the myriad of tools available (js libraries, widgets, gems, etc.).
The project itself is quite simple: basically a CRUD application with complex data entry forms.
No specific versions or needs for mobile devices.
I'd start keeping it simple: html generated by the views, css, bootstrap, jquery. Perhaps a third party component for the tables (pagination, sorting, column resizing, etc.)
I'm only afraid that, nowadays, this is simplicistic and/or outdated approach. And, since I don't have particular time constraints, I'd be glad to spend some time learning new things.
I've tried to read here and there but there are simply too options to chose from.
Any suggestions is most welcomed !