Error while migrating list with duplicated member
When migrating lists, that might have somebody subscribed twice, migrating fails with the following error:
Error: PG::UniqueViolation: ERROR: duplicate key value violates unique constraint "index_subscription
s_on_email_and_list_id"
DETAIL: Key (email, list_id)=(doubleemail@example.org, 954) already exists.
: INSERT INTO "subscriptions" ("list_id", "email", "fingerprint", "created_at", "updated_at") VALUES (
$1, $2, $3, $4, $5) RETURNING "id"
/opt/schleuder/bundler/ruby/2.3.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/post
gresql_adapter.rb:602:in `exec_prepared'