Currently there is no way in the SB Boom UI to add an Album to Favorites. You can add it to Presets, but there is no context menu to add the entire album to favorites.

A work around is to add it to favorites from the Web Remote Control, or add it as a Preset, but there should be a context menu that could allow you to select the actions such as add to Play Next, add to End of Current Playlist, and Add to Favorite.