If you commit something to a package in LHCb you should (normally) add the tag in the LHCb tag collector (https://lhcb-tag-collector.web.cern.ch/lhcb-tag-collector/index.html).
To add it:
  - Login (top right)
  - Go to New Package Revision
  - Select the package by typing in the name
  - Click in the table on "More"
  - Select the revision
  - Change (if necessary) the message
  - And hit "Add"