mix.exs

  defp deps do
    [{:ranch, "1.2.0"},
     {:uuid, "~>1.1"},
     {:json, "~>0.3.0"},
     {:cowboy, "1.0.4"}]
  end

mix.log

~/src/conman_elixir$ mix deps.get
Running dependency resolution
Dependencies have diverged:
* ranch (Hex package)
  the dependency ranch in mix.exs is overriding a child dependency:

  > In mix.exs:
    {:ranch, "1.2.0", [hex: :ranch, manager: :make]}

  > In deps/cowboy/rebar.config:
    {:ranch, "~> 1.0", [optional: false, hex: :ranch, manager: :rebar]}

  Ensure they match or specify one of the above in your deps and set "override: true"
** (Mix) Can't continue due to errors on dependencies