Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `.github/ISSUE_TEMPLATE/bug_report.md`:
  Upstream added the `bug` label to bug reports.
  Did the same.
- `app/services/fan_out_on_write_service.rb`:
  Upstream put DMs back into timelines, glitch-soc was already doing it.
  Ignored upstream changes.

lib/tasks/db.rake

@@ -48,6 +48,17 @@ namespace :db do
     end
   end
 
+  task :post_migration_hook do
+    at_exit do
+      unless %w(C POSIX).include?(ActiveRecord::Base.connection.execute('SELECT datcollate FROM pg_database WHERE datname = current_database();').first['datcollate'])
+        Rails.logger.warn 'WARNING: Your database is using an unsafe collation setting, which might result in index corruption.'
+        Rails.logger.warn 'WARNING: See https://docs.joinmastodon.org/admin/troubleshooting/index-corruption/#am-i-affected'
+      end
+    end
+  end
+
+  Rake::Task['db:migrate'].enhance(['db:post_migration_hook'])
+
   # Before we load the schema, define the timestamp_id function.
   # Idiomatically, we might do this in a migration, but then it
   # wouldn't end up in schema.rb, so we'd need to figure out a way to