minor, allow to specify database file via --database in rotz-add

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, allow to specify database file via --database in rotz-del

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, allow to specify database file via --database in rotz-show

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'cmd/all' into next

* cmd/all:
  minor, allow to specify database file via --database in rotz-show
  minor, allow to specify database file via --database in rotz-del
  minor, allow to specify database file via --database in rotz-add
doc, provide a simple README.md

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>