Add haml_lint rake task

Signed-off-by: Rémy Coutable <remy@rymai.me>

.gitlab-ci.yml

@@ -206,7 +206,7 @@ spinach 9 10 ruby21: *spinach-knapsack-ruby21
     - bundle exec $CI_BUILD_NAME
 
 rubocop: *exec
-rake haml-lint: *exec
+rake haml_lint: *exec
 rake scss_lint: *exec
 rake brakeman: *exec
 rake flog: *exec

lib/tasks/haml-lint.rake

+unless Rails.env.production?
+  require 'haml_lint/rake_task'
+
+  HamlLint::RakeTask.new do |t|
+    t.config = '.haml-lint.yml'
+    t.files = ['app/views']
+  end
+end