Dependencies
------------
 * serweb-frmwrk (https://github.com/kkozlik/serweb-frmwrk)
 * php-log
 * php-mysql
 * graphviz


Check value of session garbage collection in php.ini:
session.gc_maxlifetime = 86400


Building debian package
-----------------------
* run: debchange -i
* put changelog entries here
* run: debchange -r
* add release label to CHANGELOG file
* run: ./build-deb
* git commit -va -m "Release x.y.z"
* git tag release_x.y.z
* git push origin release_x.y.z