board.ex

  def column_winner?(_, _, _, 4) do
    true
  end

  def column_winner?(_, 1, _, _) do
    false
  end

  def column_winner?(player, row, col, count) do
    neighbor = agent_name(row-1,col)
    |> Process.whereis
    |> Agent.get(&(&1))
    
    if neighbor == player do
      column_winner?(player, row-1, col, count+1)
    else
      false
    end
  end