Add date-fns package to backend

Author: suzukalight

src/backend/package.json

@@ -41,6 +41,7 @@
     "apollo-server-express": "^2.18.2",
     "common": "file:../common",
     "cors": "^2.8.5",
+    "date-fns": "^2.16.1",
     "domain-model": "file:../domain-model",
     "dotenv": "^8.2.0",
     "express": "^4.17.1",

yarn.lock

@@ -4707,6 +4707,11 @@ date-fns@^1.27.2:
   resolved "https://registry.yarnpkg.com/date-fns/-/date-fns-1.30.1.tgz#2e71bf0b119153dbb4cc4e88d9ea5acfb50dc05c"
   integrity sha512-hBSVCvSmWC+QypYObzwGOd9wqdDpOt+0wl0KbU+R+uuZBS1jN8VsD1ss3irQDknRj5NvxiTF6oj/nDRnN/UQNw==
 
+date-fns@^2.16.1:
+  version "2.16.1"
+  resolved "https://registry.yarnpkg.com/date-fns/-/date-fns-2.16.1.tgz#05775792c3f3331da812af253e1a935851d3834b"
+  integrity sha512-sAJVKx/FqrLYHAQeN7VpJrPhagZc9R4ImZIWYRFZaaohR3KzmuK88touwsSwSVT8Qcbd4zoDsnGfX4GFB4imyQ==
+
 dateformat@~1.0.4-1.2.3:
   version "1.0.12"
   resolved "https://registry.yarnpkg.com/dateformat/-/dateformat-1.0.12.tgz#9f124b67594c937ff706932e4a642cca8dbbfee9"
@@ -4965,7 +4970,7 @@ domain-browser@^1.1.1:
   version "1.0.0"
   dependencies:
     bcrypt "^5.0.0"
-    common "file:../../Library/Caches/Yarn/v6/npm-domain-model-1.0.0-a1cdf867-6633-4dd5-94ee-3dc63ba11a20-1603102384288/node_modules/common"
+    common "file:../../Library/Caches/Yarn/v6/npm-domain-model-1.0.0-fa375160-5582-432d-a46b-890cd9373151-1603635599555/node_modules/common"
     dotenv "^8.2.0"
     graphql-scalars "^1.2.6"
     jsonwebtoken "^8.5.1"