The /index changes REST API endpoint requires the user to be a member of a group having the Administrate Server permission. This is too restrictive. Users should be able to force indexing of a change without being an administrator. Allow /index to be used by any user that can see the change, i.e. has read permission on the destination branch. Change-Id: I3734e123a2859fcd0197895c42f9676a411d5716