docs(readme): add command for locally building the pdf with docker

README.md

@@ -8,6 +8,12 @@ To create main markdown document and compile to PDF, use
 cat technical-reference-main.txt | while read LINE; do cat $LINE >> technical-reference.md ; done
 pandoc --template=rdd.latex technical-reference.md -o technical-reference.pdf
 ```
+or, for the use with docker
+
+```bash
+cat technical-reference-main.txt | while read LINE; do cat $LINE >> technical-reference.md ; done
+docker run --rm pandoc/latex -v .:/data pandoc --template=rdd.latex technical-reference.md -o technical-reference.pdf
+```
 
 Inspired by the [EURISE Network Technical Reference](https://github.com/eurise-network/technical-reference).