👔(backend) add code_editor column on Template

To save the template code editor content,
we need to add a new column on the Template model.
It is a JSONField that will store the code editor content.

We could in the future make an implementation to
save the code editor content in Minio.

src/backend/core/api/serializers.py

@@ -145,7 +145,7 @@ class TemplateSerializer(BaseResourceSerializer):
 
     class Meta:
         model = models.Template
-        fields = ["id", "title", "accesses", "abilities"]
+        fields = ["id", "title", "code_editor", "accesses", "abilities"]
         read_only_fields = ["id", "accesses", "abilities"]