After creating reader (user), I getting a lot of same requests. It's creating and deleting read_mark about 18 times.

SQL (6.7ms) DELETE FROM "read_marks" WHERE "read_marks"."reader_id" = $1 AND "read_marks"."reader_type" = $2 AND "read_marks"."readable_type" = $3 [["reader_id", 50763], ["reader_type", "User"], ["readable_type", "Event"]]

SQL (11.9ms) INSERT INTO "read_marks" ("reader_id", "reader_type", "readable_type", "timestamp") VALUES ($1, $2, $3, $4) RETURNING "id" [["reader_id", 50763], ["reader_type", "User"], ["readable_type", "Event"], ["timestamp", "2016-09-14 13:12:51.715057"]]