Add support of changes generation. Changes will be generated (unless explicitly asked not to) automatically during check process (i.e. `repo-update --dry-run` and aliases) and uploaded to the remote server. Changes can be reviewed either by web interface or by special subcommands.
Changes will be automatically cleared during next successful build
* Allow to use single web instance for any repository
* some improvements
* drop includes from user home directory, introduce new variables to docker
The old solution didn't actually work as expected, because devtools
configuration belongs to filesystem (as well as sudo one), so it was
still required to run setup command.
In order to handle additional repositories, the POSTSETUP and PRESETUP
commands variables have been introduced. FAQ has been updated as well
* raise 404 in case if repository is unknown
