iex(5)> [7]
'\a'
iex(6)> [7, 8]
'\a\b'

defmodule ToFetchQueue do
  def start_link do
    Agent.start_link(fn -> [] end, name: __MODULE__)
  end

  def add(feed_id) do
    Agent.update(__MODULE__, fn(state) ->
      state ++ [feed_id]
    end)
  end

  def get_queue() do
    Agent.get(__MODULE__, & &1)
  end

  def remove(feed_id) do
    Agent.update(__MODULE__, fn(state) ->
      List.delete(state, feed_id)
    end)
  end  

  def check_and_remove(feed_id) do
    Agent.get_and_update(__MODULE__, fn(state) ->
      is_member = Enum.member?(state, feed_id)
      {is_member, List.delete(state, feed_id)}
    end)
  end 
end

["ToFetchQueue.get_queue: ", ToFetchQueue.get_queue] |> IO.inspect

q = Ecto.Multi.new()
        |> Ecto.Multi.insert_all(:insert_all, Coins, list)


        Ecto.Adapters.SQL.to_sql(:all, Repo, q) |> IO.inspect()

conn =
      build_conn()
      |> put_req_header("accept", "application/vnd.api+json")
      |> put_req_header("content-type", "application/vnd.api+json")