Make add a postmaster user and check for its existence on

internal/store/store.go

@@ -18,6 +18,9 @@ type Interface interface {
 	SetDomain(string) error
 	SetTLS([]byte, []byte) error
 
+	CreateAccount(*Account) error
+	FindAccount(string) (*Account, error)
+
 	io.Closer
 }
 
@@ -138,6 +141,16 @@ func (c *concrete) SetTLS(certPEM, keyPEM []byte) error {
 	return nil
 }
 
+func (c *concrete) CreateAccount(a *Account) error {
+	return c.storm.Save(a)
+}
+
+func (c *concrete) FindAccount(username string) (*Account, error) {
+	var a Account
+
+	return &a, c.storm.One("Username", username, &a)
+}
+
 func (c *concrete) Close() error {
 	return c.storm.Close()
 }