Updated index.rst
Updated index.rst

In the example to setup config, the documentation forgot to prepend 'MONGODB' to the 'PASSWORD' field, and when I was using it as is, it did not authenticate. Once I changed it in my project, the password was read correctly.
rochacbruno/flask-mongoengine,quokkaproject/flask-mongoengine,quokkaproject/flask-mongoengine,losintikfos/flask-mongoengine,gerasim13/flask-mongoengine-1,gerasim13/flask-mongoengine-1,rochacbruno/flask-mongoengine,losintikfos/flask-mongoengine