Add session management for user authentication

auth/token.go

@@ -0,0 +1,19 @@
+package auth
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"time"
+)
+
+type token struct {
+	userName   string
+	created    time.Time
+	lastAccess time.Time
+}
+
+func generateKey() string {
+	key := [32]byte{}
+	rand.Read(key[:])
+	return base64.StdEncoding.EncodeToString(key[:])
+}