Update README.md

README.md

@@ -267,6 +267,8 @@ It's important to note that in the examples above, `other_item` must already bel
 
 The queries that this gem runs (especially those that seek the next position integer available) are vulnerable to race conditions. To this end, we lock the scope records to ensure that our model callbacks that determine and assign positions run sequentially. Previously we used an Advisory Lock for this purpose but this was difficult to test and a bit overkill in most situations. Where a scope doesn't exist, we lock all the records in the table.
 
+**Please Note SQLite Users:** Row locking isn't supported by SQLite. Since writes are non-concurrent by default, the worst you'll probably see are errors about the database being locked under high load.
+
 If you have any concerns or improvements please file a GitHub issue.
 
 ## Development