working on rehearsal display, also fixed some cancan abilities
added nice organized table of rehearsals with their dates. Learned about how to think about the question of displaying data in tables from Adam. Input some basic CSS Boostrap styling.
fixed redirects on rehearsal actions update, destroy and new, to return to the exercise show page.
styled much more of the exercise show page using bootstrap.
Merge pull request #13 from Henryvw/add_rehearsal_display_to_exercise_show

Add rehearsal display to exercise show