Allow to define secret key & move the secret key file to parent directory (#358)

internal/config/migrate.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// auto migration for newer versions of Opengist
+func migrateConfig() error {
+	configMigrations := []struct {
+		Version string
+		Func    func() error
+	}{
+		{"1.8.0", v1_8_0},
+	}
+
+	for _, fn := range configMigrations {
+		err := fn.Func()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func v1_8_0() error {
+	homeDir := GetHomeDir()
+	moveFile(filepath.Join(filepath.Join(homeDir, "sessions"), "session-auth.key"), filepath.Join(homeDir, "opengist-secret.key"))
+	return nil
+}
+
+func moveFile(oldPath, newPath string) {
+	if _, err := os.Stat(oldPath); err != nil {
+		return
+	}
+
+	if err := os.Rename(oldPath, newPath); err == nil {
+		fmt.Printf("Automatically moved %s to %s\n", oldPath, newPath)
+	}
+}