You have configured application with empty controller and service. Use https://docs.nestjs.com/ to find resources about framework.

Run npm i to install packages.
Run npm run lint to check code linting and cleanness.
Run npm run start to run app.

Create Mongo DB schema for entities below using NestJS Mongoose module. Docs: https://docs.nestjs.com/techniques/mongodb.

Application manages users, their hobbies and friends.
User's settings are hobby and city.
User can have many hobbies.
User can have many cities.
User can have other users as friends.
Cities and hobbies are not predefined.

List of necessary endpoints:

• user creation
• user deletion
• friend assigning
• retrieving friends of certain user
• retrieving user's friends with certain hobby
• retrieving user's friends from certain city with certain hobby
• get hobbies existent in certain city
• get cities which has users with certain hobby

Add field features for user's schema. On user's creation field features should be automatically filled with an object. Depending on hobby object should contain special property with plain list of some feature's stuff. Just array of some strings. Data can be hardcoded in project. Properties are:

• for guitar - property concerts with list of guitar concerts
• for skiing - property resorts with list of skiing resorts
• for stamp collecting - property stamps with list of stamps

Please, use strong TypeScript typing where possible.

Good luck!