percy-capybara manual parallelization setup

gistfile1.rb

# Tell Percy that this is a parallelized build. Because we separately finalize
# Percy builds, this should remain "2" no matter the actual number of nodes.
#
# Set this environment variable:
PERCY_PARALLEL_TOTAL=2

# In your spec_helper, only call `initialize_build` and not finalize:
config.before(:suite) { Percy::Capybara.initialize_build }
# Do not call `finalize_build`.

# ... run parallel tests and re-tries ...

# After all tests and re-tries have completed successfully, run:
Integer(ENV['PERCY_PARALLEL_TOTAL']).times do
  Percy::Capybara.initialize_build
  Percy::Capybara.finalize_build
end