Update README.md

README.md

@@ -36,7 +36,7 @@ To perform testing locally you need to install docker and run `yarn test:pw:dock
 
 The app instance could be customized by passing following variables to NodeJS environment at runtime.
 
-**IMPORTANT NOTE!** For _production_ build purposes all json-like values should be single-quoted
+**IMPORTANT NOTE!** For _production_ build purposes all json-like values should be single-quoted. If it contains a hash (`#`) or a dollar-sign (`$`) the whole value should be wrapped in single quotes as well (see `dotenv` [readme](https://github.com/bkeepers/dotenv#variable-substitution))
 
 ### Network configuration