You may simply use the "Task Scheduler".

In the "General" tab choose to run the task whether user is logged on or not.

In the "Triggers" tab add a new trigger that begin the task "At startup".

In the "Actions" tab add a new action that "Start a program, and in the "Program/script" field add the complete path to the Python.exe file and the arguments filed write "-m manage.py runserver" and in the "Start in" field write the path "path\of\managepyfile".

In the "Settings" tab uncheck "Stop the task if it runs longer than" option.