795 delete repository asynchonously

Shall fix #795.

I created this branch on top of #1026, not on top of staging.
Metrics/LineLength: Line is too long. [130/80]<br>Style/SpaceAroundOperators: Surrounding space missing for operator '=='.<br>Style/SpaceInsideBrackets: Space inside square brackets detected.<br>Style/SpaceInsideParens: Space inside parentheses detected.