DDD (Domain Design) partially implemented, added comments everywhere.

database/interface/databaseinterface.go

@@ -5,6 +5,8 @@ import (
 	"github.com/jmoiron/sqlx"
 )
 
+// Interface represents database interface which is available to all
+// parts of application and registers with context.Context.
 type Interface interface {
 	GetDatabaseConnection() *sqlx.DB
 	Initialize()