Store user’s nickname in memcached

[puhoshville]

Is your feature request related to a problem? Please describe.
While working with keepthis for long time you may be interested in deleting old data in store. but we can see only unique hash of data without any information about person how published that data.

Describe the solution you'd like
While setting keepthis instance at start add option to provide username. use systems username as default value.

Describe alternatives you've considered
no

Additional context
this information will be observable from memcached gui client with option to delete some cache