Update docker README docs to use yaml config file

docker/README.md

@@ -8,15 +8,46 @@ Pre-built images are available at `ghcr.io/ggozad/haiku.rag` with all extras (vo
 docker pull ghcr.io/ggozad/haiku.rag:latest
 ```
 
+## Configuration
+
+Create a configuration file `haiku.rag.yaml`:
+
+```yaml
+# haiku.rag.yaml
+environment: production
+
+embeddings:
+  provider: ollama
+  model: nomic-embed-text
+  vector_dim: 768
+
+qa:
+  provider: ollama
+  model: qwen3
+```
+
+See [Configuration docs](https://ggozad.github.io/haiku.rag/configuration/) for all available options.
+
 ## Running
 
+Mount your config file and data directory:
+
 ```bash
 docker run -p 8000:8000 -p 8001:8001 \
+  -v $(pwd)/haiku.rag.yaml:/app/haiku.rag.yaml \
   -v $(pwd)/data:/data \
-  -e EMBEDDINGS_PROVIDER=ollama \
-  -e EMBEDDINGS_MODEL=nomic-embed-text \
-  -e QA_PROVIDER=ollama \
-  -e QA_MODEL=qwen3\
+  ghcr.io/ggozad/haiku.rag:latest
+```
+
+The container will automatically use the mounted `haiku.rag.yaml` configuration file.
+
+For API keys (OpenAI, Anthropic, etc.), pass them as environment variables:
+
+```bash
+docker run -p 8000:8000 -p 8001:8001 \
+  -v $(pwd)/haiku.rag.yaml:/app/haiku.rag.yaml \
+  -v $(pwd)/data:/data \
+  -e OPENAI_API_KEY=your-key-here \
   ghcr.io/ggozad/haiku.rag:latest
 ```
 
@@ -26,8 +57,6 @@ docker run -p 8000:8000 -p 8001:8001 \
 docker build -f docker/Dockerfile -t haiku-rag .
 ```
 
-Note: The environment variables above override the defaults. See [Configuration docs](https://ggozad.github.io/haiku.rag/configuration/) for all options.
-
 ## Docker Compose
 
 See `examples/docker/` for a complete setup example.