message: For Add cases, 404 should be error response
  For AddConnectionToGroup and AddUserToGorup, if connection does not exist, or user does not exist, 404 should be considered as error response.
diff: "200": {
  "description": "Success"
  },
  - "404": {
  - "description": "Not Found"
  - },
  "default": {
  "description": "Error response",
  "schema": {
  "200": {
  "description": "Success"
  },
  - "404": {
  - "description": "Not Found"
  - },
  "default": {
  "description": "Error response",
  "schema": {
  