There's a flaky test creating a group for a budget which takes place
because toggling a form using jQuery sometimes results in the button not
being correctly clicked by Capybara.
Checking the page with `expect(page).to have_button 'Create group'`
before clicking the button doesn't solve the problem; it looks like in
those cases Capybara waits for AJAX requests but not for JavaScript
animations.
See also issue #2573.
Why:
* There is a data-equalizer attribute on the parent div, and a data-equalizer-watch on a sibiling div, and that breakes both the purpose of those values (Resize child elements of data-equalizer to have the same height. Ref: http://foundation.zurb.com/sites/docs/equalizer.html)
* That lack of attribute was breaking many specs consistently on localhost with phantomjs 2.1.1 on macos sierra (and ubuntu as reported by @amaia)
How:
* Just adding the missing 'data-equalizer-watch' attribute on the div child of the one using 'data-equalizer'
