Add direct-from-GitHub Docker build to README

Author: michalosmenda

README.md

@@ -417,15 +417,17 @@ Changing the `PC2NUTS_EXTRA_SOURCES` list invalidates the SQLite cache automatic
 
 ## Docker deployment
 
-### Build
+### Quick start (no clone needed)
 
 ```bash
-docker build -t postalcode2nuts .
+docker build -t postalcode2nuts https://github.com/bk86a/PostalCode2NUTS.git
+docker run -p 8000:8000 -v postalcode2nuts-data:/app/data postalcode2nuts
 ```
 
-### Basic run
+### Build from local clone
 
 ```bash
+docker build -t postalcode2nuts .
 docker run -p 8000:8000 postalcode2nuts
 ```