Add db:create as needed for psotgres support.
Add instructions on how to configure Postgres.
Merge pull request #1915 from VictorLowther/pull-req-master-a91d010e6f77c4fc84104247bc7752f73dab5b4d

https://github.com/crowbar/crowbar/pull/1915

Merged by devtool for cloudedge