Method/test changes in Album/AlbumRepo Classes.

-in album_repo, the following has changed:
1. find, which retrieves the album by id from the psql, changed to find_by
2. added find_all, which retrieves all albums and builds each one through .map
-following changes have been made to the album_repo tests:
1. added another object (album_object2) for testing
2. all appropriate name changes of the find method
3. added test for find_all method
4. URL in test objects changed from fake URLs to lorempixel URLs.
-All tests have passed after the changes were implemented."