[Feat] server-document에 MongoDB 연동 (ecs task definition 업데이트) (#18)

## 작업 내역 (관련 이슈)
- #17 

## 특이 사항
-

Author: Coldot

.aws/ecs-task-definition.json

@@ -20,6 +20,10 @@
             "mountPoints": [],
             "volumesFrom": [],
             "secrets": [
+                {
+                    "name": "MONGODB_URL",
+                    "valueFrom": "arn:aws:secretsmanager:ap-northeast-2:864981757354:secret:xrpedia/credentials-UAy9x0:xrpedia-mongodb-url::"
+                }
             ],
             "ulimits": [],
             "logConfiguration": {