added test that ensures searching for managements does not break the application
changed the links on the show pages of covariates, models, posteriors and species to buttons
On the show page for various items, change the text on the back button to view all
[This is a combination of 10 commits.
Original author:    yln <sourgrapes612@hotmail.com>]

Fixes for redmine issue #2162:

Added migration to add columns to the variables table and updated
index, show, edit, and new pages for variables to show and edit these
new fields to administrators.  Included a link to a CF guidelines
page.
Merge branch 'phenolphtalein-add_fields'
Merge pull request #61 from udaysaraf/fix_back_button

Fixed the back button on various pages
fixed link in searching through managements
Merge pull request #58 from udaysaraf/management_search_test

Test management search