[5102] Puma starting in cluster mode...
[5102] * Version 3.0.2 (ruby 2.3.0-p0), codename: Plethora of Penguin Pinatas
[5102] * Min threads: 1, max threads: 6
[5102] * Environment: development
[5102] * Process workers: 1
[5102] * Preloading application
[5102] ! Unable to load application: NoMethodError: undefined method `fetch' for #<Puma::LeveledOptions:0x00000002ffa8a0>