improve documentation

README.md

@@ -48,6 +48,15 @@ If you want to print labels using the _print\_label_ trigger, you may also need
 
 # Install and run
 
+## Docker
+
+Just run:
+
+    docker-compose up
+
+
+## Old-fashioned installation
+
 Be sure to have a running MongoDB server, locally. If you want to install the dependencies only locally to the current user, you can append the *--user* argument to the *pip* calls. Please also install the *python3-dev* package, before running the following commands.
 
     wget https://bootstrap.pypa.io/get-pip.py

docs/DOCKER.md

@@ -3,9 +3,12 @@
 EventMan(ager) requires MongoDB to run.
 
 You can use docker-compose.yml to have a complete environment. Run: `docker-compose up --build`
+Please notice that the *qrcode_reader.py* script is not meant to be run in a Docker container.
 
 The data is stored in the *eventman_data* volume: do not cancel it.
 
+The local *data* directory is mounted in the container: you can modify anything inside of it and changes will be reflected immediately in the running instance.
+
 In the *docker-tools* directory there is a set of tools to build and run another container to dump and restore the database; you need the docker-compose running, to execute them. From that directory you can:
 
 - **dump.sh**: dump the current database in a file like *eventman-dump-2017-11-28T21:57:43.tgz*