Implement some parts for loading data from a directory

domain.go

@@ -0,0 +1,27 @@
+package mailfull
+
+// Domain represents a Domain.
+type Domain struct {
+	name         string
+	Users        []*User
+	AliasUsers   []*AliasUser
+	CatchAllUser *CatchAllUser
+}
+
+// NewDomain creates a new Domain instance.
+func NewDomain(name string) (*Domain, error) {
+	if !validDomainName(name) {
+		return nil, ErrInvalidDomainName
+	}
+
+	d := &Domain{
+		name: name,
+	}
+
+	return d, nil
+}
+
+// Name returns name.
+func (d *Domain) Name() string {
+	return d.name
+}