Fix demo section in README.md
@@ -31,7 +31,7 @@ Clone this project to a local folder, bootstrap and start it:
```sh
git clone https://github.com/exonum/cryptocurrency
cd cryptocurrency
-SERVICE_ROOT=$(pwd)/currency_root
+export SERVICE_ROOT=$(pwd)/currency_root
./service/bootstrap.sh install
./service/bootstrap.sh enable
./service/bootstrap.sh start cryptocurrency
