When you work with a system developed over the years, you will ultimately encounter a challenge - how to solve dependencies between the pieces you put together. Sometimes you need to use two gems but they depend on different versions of another gem, so you will see in the console e.g. foo -> requires bar ~> 1.0.0, baz -> requires ~> bar 2.1.0. In this post I will propose a solution to this problem, allowing us to use two versions of a gem in our project.