Google Drive is cloud storage service and content sharing platform. Uploading a iMovie video to Google Drive on your iPad is easy. If you don't already have the Google Drive app on your iPad, you will need to download it from the Apple App store. First you need to export the videos from iMovie to camera roll on your iPad. Open 'Google Drive' app and upload videos to Google Drive with simple steps. To find your newly uploaded video, tap 'My Drive and then 'Uploads' button located in the left sidebar in your Google Drive app. The video will be called something like 'Video DATE TIME.mov', not the name you gave it within your iMovie app. You can rename it within the Google Drive app.
You can install PicBackMan's Google Drive uploader for Mac from the website and start backing up photos and videos.