text: Title: Question About Long Running Mutations And Asynchronous Tasks
  Body: Hello,
  
  We're using Flask, Graphene and SQLAlchemy on our project. The API is currently executed on our server using uWSGI and Nginx. Some of the mutations we have created trigger long running jobs (like 2 to 5 minutes). We realized that:
  - When one of the long running job is triggered / running, no other http request would be treated by our Flask application. Is this a known limitation from Graphene / SQLAlchemy? Or are we doing something wrong?
  - What would you say is the best way to manage this kind of long running request from the end user point of view? I'm thinking about returning immediately a message saying the job is triggered and then let the job run in the background, but I'm not really sure how to manage such asynchronous task in Python.
  
  Thank you
  Alexis
  