docs: add mysqld onboarding snippet

README.md

@@ -1,11 +1,27 @@
 # Panopticon
 
+> 👁️‍🗨️ It sees all.
+
+Monitoring and observability stack.
+
 ## Onboarding databases
 
-Add the following to the pod in which the database runs. Port 9187 is exposed by default by the exporter and should be mapped.
+Add the following to the pod in which the database runs.
 
 The port and exporter address should be included in `prometheus.yml`.
 
+### MySQL/MariaDB
+
+```
+podman run -d \
+  --pod <pod-name> \
+  --replace \
+  prom/mysqld-exporter \
+  --config.my-cnf=<configuration-file-path>
+```
+
+### Postgresql
+
 ```
 podman run -d \
   -e DATA_SOURCE_NAME="postgresql://<user>:<pwd>@<host>:<port>/postgres?sslmode=disable" \