Added Project References as follows.

Project                    References
=======                    =====================
ErrandBoy.Data.SqlServer   ErrandBoy.Common
                           ErrandBoy.Data

ErrandBoy.Web.Api          ErrandBoy.Common
                           ErrandBoy.Data
                           ErrandBoy.Data.SqlServer
                           ErrandBoy.Web.Api.Models
                           ErrandBoy.Web.Common

ErrandBoy.Web.Common       ErrandBoy.Common
                           ErrandBoy.Data