yalab

$ echo 'gem "webpacker"' >> Gemfile
$ bundle install
$ rails webpacker:install
$ yarn add bootstrap@4.0.0-beta jquery popper.js

diff --git a/config/webpack/environment.js b/config/webpack/environment.js
index d16d9af..86bf1a7 100644

zhengjia

=Navigating=
    visit('/projects')
    visit(post_comments_path(post))

=Clicking links and buttons=
    click_link('id-of-link')
    click_link('Link Text')
    click_button('Save')
    click('Link Text') # Click either a link or a button
    click('Button Value')