Add Docker command in erasure code document (minio#4735)

docs/erasure/README.md

@@ -26,12 +26,27 @@ Install Minio - [Minio Quickstart Guide](https://docs.minio.io/docs/minio-quicks
 
 ### 2. Run Minio Server with Erasure Code.
 
-Example: Start Minio server in a 12 drives setup.
+Example: Start Minio server in a 12 drives setup, using Minio binary.
 
 ```sh
 minio server /mnt/export1/backend /mnt/export2/backend /mnt/export3/backend /mnt/export4/backend /mnt/export5/backend /mnt/export6/backend /mnt/export7/backend /mnt/export8/backend /mnt/export9/backend /mnt/export10/backend /mnt/export11/backend /mnt/export12/backend
 ```
 
+Example: Start Minio server in a 8 drives setup, using Minio Docker image. 
+
+```sh
+docker run -p 9000:9000 --name minio \
+  -v /mnt/export1/backend:/export1 \
+  -v /mnt/export2/backend:/export2 \
+  -v /mnt/export3/backend:/export3 \
+  -v /mnt/export4/backend:/export4 \
+  -v /mnt/export5/backend:/export5 \
+  -v /mnt/export6/backend:/export6 \
+  -v /mnt/export7/backend:/export7 \
+  -v /mnt/export8/backend:/export8 \
+  minio/minio server /export1 /export2 /export3 /export4 /export5 /export6 /export7 /export8
+```
+
 ### 3. Test your setup
 
 You may unplug drives randomly and continue to perform I/O on the system.