Docker: opsdroid should not be a member of root (#1898)
Docker: opsdroid should not be a member of root (#1898)

There is no need that the user opsdroid is member
of the group root. It is also not an system account since
it has an uid > 999. Instead set no password.
jacobtomlinson/opsdroid,opsdroid/opsdroid,FabioRosado/opsdroid