Update README.md with CI best practices.

README.md

@@ -17,13 +17,26 @@ Create `~/.config/it.linux.golem/component.conf` with following content:
     username=golem
     password=guess
 
-## Dependencies
-On Debian/Ubuntu/Mint:
-* qt5-default
-* TODO
-
-# Build
+## Build
+Download the build container:
 ```
-script/build
+docker pull git.golem.linux.it/golem/gestionale-build
 ```
 
+Or, if you prefer, you can also build it by yourself:
+```
+script/setup
+```
+
+Then, run all the commands in the build container, simply by preceding them with `docker`.
+Example:
+```
+./docker ls
+```
+
+Every command you'll ever need to build this software should be scripted inside the `script/` directory.
+
+Example: compile everything and produce executable.
+```
+./docker script/build
+```