Refactor JWT auth and remove DB dependency from config

internal/auth/jwt.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"CatsOfMastodonBotGo/internal/config"
 	"strings"
 	"time"
 
@@ -14,11 +15,13 @@ type JwtTokenGenerator struct {
 	Audience string
 }
 
-func NewJwtTokenGenerator(key string, issuer string, audience string) *JwtTokenGenerator {
-	return &JwtTokenGenerator{
-		Key: key,
-		Issuer: issuer,
-		Audience: audience,
+var JwtTokenGeneratorInstance *JwtTokenGenerator
+
+func InitJwtTokenGenerator() {
+	JwtTokenGeneratorInstance = &JwtTokenGenerator{
+		Key:  config.Config.JwtSecret,
+		Issuer: config.Config.JwtIssuer,
+		Audience: config.Config.JwtAudience,
 	}
 }