Add method to add users to groups

model/src/lib.rs

@@ -68,6 +68,12 @@ pub struct CreateGroupRequest {
     pub display_name: String,
 }
 
+#[derive(PartialEq, Eq, Debug, Serialize, Deserialize)]
+pub struct AddUserToGroupRequest {
+    pub user_id: String,
+    pub group_id: i32,
+}
+
 #[derive(Clone, Serialize, Deserialize)]
 pub struct JWTClaims {
     pub exp: DateTime<Utc>,