Explore Rails built-in performance testing

[kaylareopelle]

Our perf test suite needs some work. Let's look at the Rails perf testing strategy to see if there's something we could leverage.

• https://guides.rubyonrails.org/v3.2/performance_testing.html
• https://railsg.xyz/benchmark
• https://github.com/rails/rails-perftest

[workato-integration]

https://new-relic.atlassian.net/browse/NR-181327