i want to write a small rust program that exposes an http endpoint, and integrates with mongodb.
heres a description of what the program should do:
- expose an http endpoint that takes a path parameter on "/org/[9-digit number]", and return the json object identified by that 9-digit number in the db. 
- if the object is not in the db, search this api:
"https://data.brreg.no/enhetsregisteret/api/enheter/[9-digit number]/roller" for the information, and insert it into the db, and also return it to the http endpoint the program exposes. 
- the db credentials are user: "user" and password: "pass", the db url is "mongodb.local" 

plese request additional information if it is needed to complete the program.