Why do you use open-source libraries? Why not build everything from scratch?
There’s a common misconception that open-source means low-quality, when the opposite is actually true. The open-source community, especially in Ruby, is extremely active, fueled by developers who love writing Ruby, and who care about writing code well. Aside from the added time (and cost) of developing everything in-house, leveraging popular open-source libraries is a wise choice because they have been battle-tested by many others beforehand. Why spend valuable time and money on something that isn’t the core of your product?