My loopback model-relation is not working - mongodb

Question

As I created my user model on top of User-built in model and created a new model library. But if I'm trying to make a relationship its giving the error "unauthorized".
Here are my files:
user.json
{
"name": "user",
"base": "User",
"idInjection": true,
"options": {
"validateUpsert": true
},
"properties": {
"phone": {
"type": "string"
},
"age": {
"type": "string"
}
},
"validations": [],
"relations": {
"library": {
"type": "hasMany",
"model": "Library",
"foreignKey": ""
}
},
"acls": [
{
"accessType": "*",
"principalType": "ROLE",
"principalId": "$everyone",
"permission": "ALLOW"
}
],
"methods": {}
}
and my library.json
{
"name": "Library",
"base": "PersistedModel",
"strict": false,
"idInjection": true,
"options": {
"validateUpsert": true
},
"properties": {
"category": {
"type": "string"
},
"bookTitle": {
"type": "string"
},
"author": {
"type": "string",
"required": true,
"index": false
}
},
"validations": [],
"relations": {
"user": {
"type": "belongsTo",
"model": "user",
"foreignKey": ""
}
},
"acls": [
{
"accessType": "*",
"principalType": "ROLE",
"principalId": "$everyone",
"permission": "ALLOW"
}
],
"methods": {}
}
As you could see that foreign key is empty what exactly it means I don't know why we need to left empty that and user login is working fine. It returns me the access token which I'm setting at the top right.
I didn't find the appropriate answer as I'm saving my database to MongoDB.

Answer 1

please try this add in library.json
"acls": [
{
"accessType": "*",
"principalType": "ROLE",
"principalId": "$owner",
"permission": "ALLOW"
}
]
and in user.json file add these
"acls": [
{
"accessType": "*",
"principalType": "ROLE",
"principalId": "$everyone",
"permission": "ALLOW"
},{
"principalType": "ROLE",
"principalId": "$owner",
"permission": "ALLOW"
}
],
u need to give the owner permission for both the models.
Please let me know if you are facing any issue