Upgrade Rails to 4.1.5

Stay current with security releases.

Also: Fix tests.
Update gems in bundle.

Here's what changed:
Installing better_errors 2.0.0 (was 1.1.0)
Installing nokogiri 1.6.3.1 (was 1.6.2.1)
Installing capybara 2.4.1 (was 2.3.0)
Installing coffee-script-source 1.8.0 (was 1.7.0)
Installing execjs 2.2.1 (was 2.2.0)
Installing coffee-script 2.3.0 (was 2.2.0)
Installing devise 3.3.0 (was 3.2.4)
Installing faker 1.4.3 (was 1.4.2)
Installing font-awesome-sass 4.2.0 (was 4.1.0)
Installing hashie 3.3.1 (was 2.1.2)
Installing jbuilder 2.1.3 (was 2.1.1)
Installing minitest-rails 2.1.0 (was 2.0.3)
Installing minitest-rails-capybara 2.1.1 (was 2.0.1)
Installing oauth2 1.0.0 (was 0.9.4)
Installing omniauth 1.2.2 (was 1.2.1)
Installing omniauth-oauth2 1.2.0 (was 1.1.2)
Installing slop 3.6.0 (was 3.5.0)
Installing pundit 0.3.0 (was 0.2.3)
Installing sdoc 0.4.1 (was 0.4.0)
Installing turbolinks 2.3.0 (was 2.2.2)
Installing uglifier 2.5.3 (was 2.5.1)
Restrict access to edit/update actions.

Fixes #5.
Merge pull request #21 from bwstud/issue-5-br

Restrict access to edit/update actions.