Uncaught TypeError: Cannot convert a Symbol value to a string
    at Array.toString (native)
    at Array.toString (native)
    at http://localhost:8080/elixir/elixirscript.build.js:1423:2057
    at Object._for (http://localhost:8080/elixir/elixirscript.build.js:1423:4708)
    at recur (http://localhost:8080/elixir/elixirscript.build.js:6366:48)
    at Object.trampoline$1 [as trampoline] (http://localhost:8080/elixir/elixirscript.build.js:1423:4297)
    at setup (http://localhost:8080/elixir/elixirscript.build.js:6382:44)
    at recur (http://localhost:8080/elixir/elixirscript.build.js:6396:40)
    at Object.trampoline$1 [as trampoline] (http://localhost:8080/elixir/elixirscript.build.js:1423:4297)
    at Object.start (http://localhost:8080/elixir/elixirscript.build.js:6402:44)