[testing] add turbo tests (#1091)

README.md

@@ -1280,6 +1280,7 @@ Online tools, services and APIs to simplify development.
   * [Ruby-JMeter](https://github.com/flood-io/ruby-jmeter) - A Ruby based DSL for building JMeter test plans.
   * [Spring](https://github.com/rails/spring) - Preloads your rails environment in the background for faster testing and Rake tasks.
   * [timecop](https://github.com/travisjeffery/timecop) - Provides "time travel" and "time freezing" capabilities, making it dead simple to test time-dependent code.
+  * [Turbo Tests](https://github.com/serpapi/turbo_tests) - Run RSpec tests on multiple cores. Like `parallel_tests` but with incremental summarized output.
   * [vcr](https://github.com/vcr/vcr) - Record your test suite's HTTP interactions and replay them during future test runs for fast, deterministic, accurate tests.
   * [Wraith](https://github.com/BBC-News/wraith) - A responsive screenshot comparison tool.
   * [Zapata](https://github.com/Nedomas/zapata) - Who has time to write tests? This is a revolutionary tool to make them write themselves.