Added user permissions, delete user

src/backend/models/user.js

@@ -3,8 +3,9 @@
 
 'use strict';
 
-const db    = require('../db');
-const Model = require('objection').Model;
+const db             = require('../db');
+const Model          = require('objection').Model;
+const UserPermission = require('./user_permission');
 
 Model.knex(db);
 
@@ -30,6 +31,22 @@ class User extends Model {
         return ['roles'];
     }
 
+    static get relationMappings () {
+        return {
+            permissions: {
+                relation:   Model.HasOneRelation,
+                modelClass: UserPermission,
+                join:       {
+                    from: 'user.id',
+                    to:   'user_permission.user_id'
+                },
+                modify:     function (qb) {
+                    qb.omit(['id', 'created_on', 'modified_on', 'user_id']);
+                }
+            }
+        };
+    }
+
 }
 
 module.exports = User;