app/assets/stylesheets/application.css
add
app/views/boards/index.html.erb
app/assets/stylesheets/application.css.scss
app/controllers/boards_controller.rb
app/views/boards/new.html.erb
app/controllers/boards_controller.rb
app/views/boards/edit.html.erb
app/views/boards/show.html.erb
app/assets/stylesheets/application.css.scss