fix: hotbugs in multi-tenant arch.

server/src/models/ResourceFieldMetadata.js

@@ -1,5 +1,3 @@
-import { Model } from 'objection';
-import path from 'path';
 import TenantModel from '@/models/TenantModel';
 import ResourceFieldMetadataCollection from '@/collection/ResourceFieldMetadataCollection';
 
@@ -17,23 +15,4 @@ export default class ResourceFieldMetadata extends TenantModel {
   static get collection() {
     return ResourceFieldMetadataCollection;
   }
-
-  /**
-   * Relationship mapping.
-   */
-  static get relationMappings() {
-    return {
-      /**
-       * Resource field may belongs to resource model.
-       */
-      resource: {
-        relation: Model.BelongsToOneRelation,
-        modelBase: path.join(__dirname, 'Resource'),
-        join: {
-          from: 'resource_fields.resource_id',
-          to: 'resources.id',
-        },
-      },
-    };
-  }
 }