Mongo Service

Error

21:40:59.077 [info]  Started MongoService

21:40:59.077 [info]  Started populating Urls

=INFO REPORT==== 22-Dec-2014::21:41:00 ===
    application: logger
    exited: stopped
    type: temporary

=INFO REPORT==== 22-Dec-2014::21:41:00 ===
    application: httpoison
    exited: stopped
    type: temporary

=INFO REPORT==== 22-Dec-2014::21:41:00 ===
    application: hackney
    exited: stopped
    type: temporary

=INFO REPORT==== 22-Dec-2014::21:41:00 ===
    application: idna
    exited: stopped
    type: temporary
** (Mix) Could not start application jobboard: exited in: JB.start(:normal, [])
    ** (EXIT) exited in: GenServer.call(:mongo_service, {:get, #Function<2.24609682/1 in MongoService.insert/2>}, 5000)
        ** (EXIT) no process

gistfile1.ex

 def start_link do
    {:ok, pid} = Agent.start_link(fn ->
      mongo = Mongo.connect!
      db = mongo |> Mongo.db("simply_hired_urls")
      collection = db |> Mongo.Db.collection("urls")
    end,
    name: :mongo_service)

    Logger.info "Started MongoService"
    {:ok, pid}
  end

  def insert(query, object) do
    collection = Agent.get(:mongo_service, fn connection -> connection end)
    Mongo.Collection.update(collection, query, object, true)
  end

My error is:

** (Mix) Could not start application jobboard: exited in: JB.start(:normal, [])
** (EXIT) exited in: GenServer.call(:mongo_service, {:get, #Function<2.24609682/1 in MongoService.insert/2>}, 5000)
** (EXIT) no process