Performance testing

[jure]

Given that we do want to make this app really 🚤, we need a way to reliably test its performance for the various user flows (more info here #43 (comment))

Here's a few starting points:
http://guides.rubyonrails.org/v3.2.18/performance_testing.html
https://github.com/rails/rails-perftest
https://github.com/sinisterchipmunk/rspec-prof
http://railscasts.com/episodes/411-performance-testing

[mfenner]

Makes a lot of sense to me to move to a formal test suite for performance testing.

Historically the bottleneck has been the ALM API delivering stats for large numbers of articles (e.g. 500).