Add some ruminations about how Things, Actions and Keys relate
- `cmd/weaviate-server/main.go`
- The file `restapi/configure_weaviate.go` is partially automatically generated, partially hand-edited.
+## Data Model
+- Weaviate stores Things, Actions and Keys.
+- Keys are used both for authentication and authorization in Weaviate.
+- Owners of a key can create more keys; the new key points to the parent key that is used to create the key.
+- Permissions (read, write, delete, execute) are linked to a key.
+- Each piece of data (e.g. Things & Actions) is associated with a Key.
+
## Dockerized development environment
### Build and run Weaviate
