Update dev server instructions

.envrc

@@ -1,4 +1,5 @@
 layout python3
 
 export QUART_APP=snikket_web:app
+export QUART_ENV=development
 export SNIKKET_WEB_CONFIG="$(pwd)/.local/web_config.py"

README.md

@@ -8,5 +8,7 @@ $ mkdir .local
 $ cp web_config.example.py .local/web_config.py
 $ $EDITOR .local/web_config.py  # to adapt the configuration to your needs
 $ pip install -r requirements.txt
+$ pip install -r build-requirements.txt
+$ make
 $ quart run
 ```