dot_spacemacs.el

  ;; from http://www.lunaryorn.com/2015/04/29/the-power-of-display-buffer-alist.html
  (add-to-list 'display-buffer-alist
               `(,(rx bos (or
                           "*rspec-compilation*"
                           "*projectile-rails-compilation*"
                           "*Bundler*"
                           "*alchemist test report*"
                           "*alchemist mix*"
                           "*elixir help*"
                           "*alchemist help*"
                           "*mix*")
                      eos)
                 (display-buffer-reuse-window
                  display-buffer-in-side-window)
                 (reusable-frames . visible)
                 (side            . bottom)
                 (window-height   . 0.4)))