Update polygerrit-ui/README.md with some developer scenarios
Update polygerrit-ui/README.md with some developer scenarios

Change-Id: I1716b9ed332bb2eab2db36cecb33db63c3320958

joshuawilson/merrit,joshuawilson/merrit,gerrit-review/gerrit,GerritCodeReview/gerrit,joshuawilson/merrit,qtproject/qtqa-gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,joshuawilson/merrit,GerritCodeReview/gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,MerritCR/merrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,WANdisco/gerrit,MerritCR/merrit,joshuawilson/merrit,gerrit-review/gerrit,MerritCR/merrit,gerrit-review/gerrit,gerrit-review/gerrit,MerritCR/merrit,GerritCodeReview/gerrit,joshuawilson/merrit,WANdisco/gerrit,gerrit-review/gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,WANdisco/gerrit,gerrit-review/gerrit,qtproject/qtqa-gerrit,WANdisco/gerrit,GerritCodeReview/gerrit,MerritCR/merrit,gerrit-review/gerrit,joshuawilson/merrit,MerritCR/merrit,joshuawilson/merrit,MerritCR/merrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit