Add password hashing with argon2

internal/auth/credentials.go

@@ -1,10 +1,18 @@
 package auth
 
-import "errors"
+import (
+	"errors"
+
+	"github.com/Bronku/iroon/internal/crypto"
+)
 
 func (a *Authenticator) verifyCredentials(login, password string) error {
-
-	if login == "admin" && password == "secret" {
+	user, ok := a.s.GetUser(login)
+	if !ok {
+		return errors.New("user with this login doesn't exist")
+	}
+	hash := crypto.PasswordHash(password, user.Salt)
+	if hash == user.Password {
 		return nil
 	}
 	return errors.New("wrong credentials")