Learning which gems to use has always lead to a couple hours of scouring github, or other blogs to find out which ones are most useful. I’d like to see which ones you use and how they’re useful. I’ll start with one:
“Did You Mean?” GEM. This bad boy is great for correcting misspelled methods or classes. Great for beginners to use in your test/production environment. It’s sort of like linting for Ruby, but for run-time fixes.