Explore the world of open source

Using this search engine (with Ruby/Rails gem) and am very happy. Performance is blazing fast.

Middleman is underrated. It's still one of the best frameworks to build static sites. It works nice for simple websites, for blogs, and due to some of its features (data + proxy + config as code), you can also build more sophisticated static web-apps.

While it is probably the most customizable and flexible gem for file uploads, it might be too complex. I personally prefer to use a paperclip, carrierwave, or activestorage when I need to have just a simple file upload.

Great library if you want to add feature flags to your app. I like the flexibility and ability to fully/partially/specifically enable features.

top

Very useful gem to run distributed "cron" tasks over Redis. It works with minimal setup, you just need to define a YAML with your tasks and their scheduling time (that can be defined in natural language: "every 6 hours").