add jwt token validation

main.go

@@ -95,7 +95,7 @@ func loginHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	expirationTime := time.Now().Add(15 * time.Minute)
+	expirationTime := time.Now().Add(120 * time.Minute)
 	claims := &Claims{
 		Username: creds.Username,
 		RegisteredClaims: jwt.RegisteredClaims{