Do not require Pronto when running the application

Pronto is an external tool which is use to check code conventions and is
not needed to run the application, just like rubocop or scss-lint.

Loading it caused a couple of issues. First, it loaded BetterHtml, and
we had to disable it in order to avoid crashes in the development
environment.

Second, it loaded ruby-progressbar, which loads the ProgressBar class,
which conflicts with our own ProgressBar class. This made the
application crash whenever the ProgressBar class was used.

Gemfile

@@ -102,11 +102,11 @@ group :development do
   gem "erb_lint", "~> 0.0.35", require: false
   gem "github_changelog_generator", "~> 1.15.2"
   gem "mdl", "~> 0.11.0", require: false
-  gem "pronto", "~> 0.11.0"
-  gem "pronto-erb_lint", "~> 0.1.5"
-  gem "pronto-eslint", "~> 0.11.0"
-  gem "pronto-rubocop", "~> 0.11.0"
-  gem "pronto-scss", "~> 0.11.0"
+  gem "pronto", "~> 0.11.0", require: false
+  gem "pronto-erb_lint", "~> 0.1.5", require: false
+  gem "pronto-eslint", "~> 0.11.0", require: false
+  gem "pronto-rubocop", "~> 0.11.0", require: false
+  gem "pronto-scss", "~> 0.11.0", require: false
   gem "rubocop", "~> 0.91.0", require: false
   gem "rubocop-performance", "~> 1.7.1", require: false
   gem "rubocop-rails", "~> 2.6.0", require: false

config/initializers/better_html.rb

@@ -1,5 +0,0 @@
-if Rails.env.development?
-  BetterHtml.configure do |config|
-    config.template_exclusion_filter = proc { |filename| true }
-  end
-end