Label text color comes from JSON

app/assets/javascripts/dispatcher.js.coffee

app/assets/javascripts/issuable.js.coffee

app/assets/javascripts/issues.js.coffee

app/assets/javascripts/labels_select.js.coffee

app/assets/javascripts/merge_requests.js.coffee

app/assets/javascripts/milestone_select.js.coffee

app/assets/javascripts/users_select.js.coffee

app/controllers/projects/issues_controller.rb

app/controllers/projects/merge_requests_controller.rb

app/models/label.rb

app/views/shared/issuable/_filter.html.haml