Debugging cucumber scenarios in Rubymine is wonderfully simple. Here’s how i do it:
Create a cucumber step that puts the app into debug mode and pops open the current page that’s being debugged

I use Rubymine’s gutter breakpoints, and I add the breakpoint after the save_and_open_page method call, so the page pops open before entering the debugger.
Insert the step into whichever scenario i wish to debug

Run the scenario in debug mode

Inspect the app’s objects in Rubymine’s Watches

Pretty sweet! Super easy and extremely useful.
Rubymine’s a great app, and i’m just starting to scratch the surface.