consider all sqlite DATABASE_URLs local.

lib/database_cleaner/safeguard.rb

@@ -15,7 +15,7 @@ module DatabaseCleaner
     end
 
     class RemoteDatabaseUrl
-      LOCAL = %w(localhost 127.0.0.1)
+      LOCAL = %w(localhost 127.0.0.1 sqlite3:)
 
       def run
         raise Error::RemoteDatabaseUrl if !skip? && given?

spec/database_cleaner/safeguard_spec.rb

@@ -36,6 +36,14 @@ module DatabaseCleaner
         end
       end
 
+      describe 'to a sqlite db' do
+        let(:database_url) { 'sqlite3:tmp/db.sqlite3' }
+
+        it 'does not raise' do
+          expect { cleaner.start }.to_not raise_error
+        end
+      end
+
       describe 'DATABASE_CLEANER_ALLOW_REMOTE_DATABASE_URL is set' do
         let(:database_url) { 'postgres://remote.host' }
         before { stub_const('ENV', 'DATABASE_CLEANER_ALLOW_REMOTE_DATABASE_URL' => true) }