[chore]click "invite users" will hide the overlay
Merge pull request #80 from peterzd/fix_upload_image

[chore]click "invite users" will hide the overlay
[feature]add following cards page
[chore]authorize for follow and unfollow actions
[feature]user can list his hidden cards
[chore]fix bug for album_decorator
[chore]fix bugs to make albums_controller_test pass
Merge pull request #81 from peterzd/follow_hidden_page

Follow hidden page
Merge pull request #82 from peterzd/dev

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