docs(dev): info on how to generate api model

docs/developer-guide.md

@@ -80,6 +80,16 @@ Test cases are located in `./tests` are executed by running:
 
 You can find the AURA API definition at https://api.aura.radio
 
+Engine utilizes the Steering API and Tank API to query scheduling and playlist data.
+
+The OpenAPI specification for these APIs are located in `schemas` and used for the client models.
+
+To generate the API client models run
+
+```bash
+make api
+```
+
 ## Scheduler
 
 Scheduling is split into multiple phases. Below you see a timeline with one timeslot planned at a certain