         :ok = Config.put(project_name, %__MODULE__{project | enabled: true,
           observer: observer})
         :ok = Observer.run(observer)
+        true
       end
   end
 

  @doc """
  Disables the project and stop the observer's work.
  """
  def disable(project_name) do
    with {:ok, project} = Config.config(project_name),
      true = project.enabled
      do
        :ok = Observer.stop(project.observer, :stop)
        put_disabled_project(project_name, project)
      end
  end
end

  @doc """
  Enables the project and let the observer do its work.
  """
  @spec enable(String.t) :: bool
  def enable(project_name) do
    with {:ok, project} = Config.config(project_name),
      false <- project.enabled
      do
        {:ok, observer} = Supervisor.start_child(Baumeister.ObserverSupervisor,
          [project_name])
