Set paddle direction correctly

game.ex

@spec move_paddle(Socket.t(), :left | :right) :: Socket.t()
defp move_paddle(%{assigns: %{paddle: paddle}} = socket, direction) do
  if paddle.direction == direction do
    socket
  else
    assign(socket, :paddle, %{paddle | direction: direction})
  end
end

@spec stop_paddle(Socket.t(), :left | :right) :: Socket.t()
defp stop_paddle(%{assigns: %{paddle: paddle}} = socket, direction) do
  if paddle.direction == direction do
    assign(socket, :paddle, %{paddle | direction: :stationary})
  else
    socket
  end
end