Wrap logic of the insert! macro in a transaction

plume-models/src/lib.rs

@@ -261,6 +261,8 @@ macro_rules! insert {
 
         #[allow(dead_code)]
         pub fn insert(conn: &crate::Connection, new: $from) -> Result<Self> {
+            use diesel::connection::Connection as _;
+            conn.transaction::<_, Error, _>(|| {
                 diesel::insert_into($table::table)
                     .values(new)
                     .execute(conn)?;
@@ -268,6 +270,7 @@ macro_rules! insert {
                 let mut $val = Self::last(conn)?;
                 let $conn = conn;
                 $( $after )+
+            })
         }
     };
 }