If you can’t beat them, join them. That must have been the idea at General Motors, thinking about services like Uber and Lyft, when it decided to create a car-sharing service called Maven. It is now launched in the United States and Germany, joining at least two other automakers testing the market for consumers who want to borrow cars rather than own them. Use of a small car starts at as little as $6 per hour or $12 per hour for a large car, according to website MavenDrive.com.