rib 1.6.0

Ruby-Interactive-ruBy -- Yet another interactive Ruby shell Rib is based on the design of [ripl][] and the work of [ripl-rc][], some of the features are also inspired by [pry][]. The aim of Rib is to be fully featured and yet very easy to opt-out or opt-in other features. It shall be simple, lightweight and modular so that everyone could customize Rib. [ripl]: https://github.com/cldwalker/ripl [ripl-rc]: https://github.com/godfat/ripl-rc [pry]: https://github.com/pry/pry