Add a section on setting up MongoDB

README.md

@@ -185,3 +185,61 @@ variable. It works in the following way:
   `TRACE_LEVEL_FILTER="src.api.foo.foobar,src.api.bar.barfoo"`
 - When `TRACE_LEVEL_FILTER` starts with a `!` symbol, followed by a list of loggers, the root logger will be set to
   `TRACE` level, with the specified loggers being set to `DEBUG` level.
+
+### MongoDB
+
+As you probably noticed, the project uses MongoDB as the database. If you're not familiar with MongoDB, it's a NoSQL
+database, which is very easy to use and set up. You can find more information about it on the [official MongoDB
+website](https://www.mongodb.com/).
+
+To set up a MongoDB instance, you can either use the provided docker-compose file, in which case you don't need to do
+anything, or set it up manually. For manual setup, you can follow the [official installation
+guide](https://docs.mongodb.com/manual/installation/).
+
+#### Quick MongoDB setup
+
+If you just need a quick MonogDB instance that you can spin up during the development, I'd recommend using Docker. Note
+that you don't need to follow the Docker installation for the entire project, e.g. using docker-compose, you can run the
+project normally and just host the MongDB instance through Docker. To do this, simply run:
+
+```bash
+sudo docker run -d --name mongodb \
+  -e MONGO_INITDB_ROOT_USERNAME=root \
+  -e MONGO_INITDB_ROOT_PASSWORD=test \
+  -p 27017:27017 \
+  mongo:latest
+```
+
+This will start a MongoDB instance with the root user having the username `root` and password `test`, using the admin
+`authSource`. The instance will be available on port 27017, so you can use it with the following connection string:
+
+```dotenv
+MONGODB_URI=mongodb://root:test@localhost:27017/my-cool-database?authSource=admin
+```
+
+Once you're done, you can stop the instance by running:
+
+```bash
+sudo docker stop mongodb
+```
+
+To also remove the container, you can run:
+
+```bash
+sudo docker remove mongodb
+```
+
+> [!NOTE]
+> This MongoDB instance will not persist the data across runs. If you remove the container, all the data will be lost.
+> If you need the data to persist, you can use a docker volume or a bind mount, as already explained in the
+> [Docker](#docker) section.
+
+#### Quickly populate the database
+
+During the development, it's often useful to have some data in the database to work with. To quickly populate the
+database with some, you can use the provided `populate_db.py` script. To run it, make sure you have activated the
+virtual environment and then run:
+
+```bash
+python populate_db.py
+```