Use filesystem session store (#240)

internal/utils/session.go

@@ -0,0 +1,26 @@
+package utils
+
+import (
+	"github.com/gorilla/securecookie"
+	"github.com/rs/zerolog/log"
+	"os"
+)
+
+func ReadKey(filePath string) []byte {
+	key, err := os.ReadFile(filePath)
+	if err == nil {
+		return key
+	}
+
+	key = securecookie.GenerateRandomKey(32)
+	if key == nil {
+		log.Fatal().Msg("Failed to generate a new key for sessions")
+	}
+
+	err = os.WriteFile(filePath, key, 0600)
+	if err != nil {
+		log.Fatal().Err(err).Msgf("Failed to save the key to %s", filePath)
+	}
+
+	return key
+}