Revert "DbManager and UserManager works"

This reverts commit a17bfa41671084700383c7e2dd08c901e4fb0b02.
Revert "Revert "DbManager and UserManager works""

This reverts commit 6d574d18b7243c7d6b2bfd1e9ce3ea8729587417.
Merge remote-tracking branch 'origin/master'