server: Add domain support for creating/deleting attributes

server/src/domain/handler.rs

@@ -137,6 +137,15 @@ pub struct AttributeSchema {
     pub is_hardcoded: bool,
 }
 
+#[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone)]
+pub struct CreateAttributeRequest {
+    pub name: String,
+    pub attribute_type: AttributeType,
+    pub is_list: bool,
+    pub is_visible: bool,
+    pub is_editable: bool,
+}
+
 #[derive(PartialEq, Eq, Debug, Serialize, Deserialize, Clone)]
 pub struct AttributeList {
     pub attributes: Vec<AttributeSchema>,
@@ -200,6 +209,15 @@ pub trait ReadSchemaBackendHandler {
     async fn get_schema(&self) -> Result<Schema>;
 }
 
+#[async_trait]
+pub trait SchemaBackendHandler: ReadSchemaBackendHandler {
+    async fn add_user_attribute(&self, request: CreateAttributeRequest) -> Result<()>;
+    async fn add_group_attribute(&self, request: CreateAttributeRequest) -> Result<()>;
+    // Note: It's up to the caller to make sure that the attribute is not hardcoded.
+    async fn delete_user_attribute(&self, name: &str) -> Result<()>;
+    async fn delete_group_attribute(&self, name: &str) -> Result<()>;
+}
+
 #[async_trait]
 pub trait BackendHandler:
     Send