login.ex

  def connect(%{"username" => username, "chat_token" => chat_token}, socket) do
    case Repo.get_by(User, username: username) do
      nil ->
        :error
      user ->
        if user.chat_token == chat_token do
          socket = assign(socket, :current_user, user)
          {:ok, socket}
        else
          :error
        end
    end
  end