fix cucumber test

[#77974930]
Fix delete button on Book#index

[Finishes #77999618]
fix test for activate

[#78001164]
move buttons to Book#show in the UI

[Finishes #78000520]
added cucumber-slices gem, and some test helpers

[#78001164]
Merge pull request #29 from psytau/tests-for-admin

Tests for admin