Add dev.yml

[kmcphillips]

@jonathankwok @thegedge cc @burke

Related to https://github.com/Shopify/measured/pull/26

~/source/measured-rails(master ✗) dev up
✓ 1/2: Installing Ruby (nothing to do)
┏━━ 🦄  2/2: Running Bundler ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
┃ ✓ install bundler (nothing to do)
┃ bundle install
┃ Fetching gem metadata from https://rubygems.org/...........
┃ Fetching version metadata from https://rubygems.org/...
┃ Fetching dependency metadata from https://rubygems.org/..
┃ Resolving dependencies...
┃ Using rake 10.4.2
┃ Using minitest 5.5.1
┃ Using thread_safe 0.3.5
┃ Using builder 3.2.2
┃ Using erubis 2.7.0
┃ Using mini_portile2 2.0.0
┃ Using i18n 0.7.0
┃ Using json 1.8.3
┃ Installing arel 6.0.3
┃ Using bundler 1.11.2
┃ Using coderay 1.1.0
┃ Installing mime-types 2.99
┃ Installing rack 1.6.4
┃ Using thor 0.19.1
┃ Using metaclass 0.0.4
┃ Using method_source 0.8.2
┃ Using slop 3.6.0
┃ Using tzinfo 1.2.2
┃ Installing concurrent-ruby 1.0.0
┃ Installing sqlite3 1.3.10 with native extensions
┃ Installing mail 2.6.3
┃ Using mocha 1.1.0
┃ Using pry 0.10.1
┃ Installing nokogiri 1.6.7.1 with native extensions
┃ Installing rack-test 0.6.3
┃ Using activesupport 4.2.5
┃ Installing sprockets 3.5.2
┃ Installing rails-deprecated_sanitizer 1.0.3
┃ Installing globalid 0.3.6
┃ Installing activemodel 4.2.5
┃ Installing activejob 4.2.5
┃ Installing measured 1.4.0
┃ Installing activerecord 4.2.5
┃ Installing rails-dom-testing 1.0.7
┃ Installing loofah 2.0.3
┃ Installing rails-html-sanitizer 1.0.2
┃ Installing actionview 4.2.5
┃ Installing actionpack 4.2.5
┃ Installing sprockets-rails 3.0.0
┃ Installing actionmailer 4.2.5
┃ Installing railties 4.2.5
┃ Using measured-rails 1.4.0 from source at `.`
┃ Installing rails 4.2.5
┃ Bundle complete! 7 Gemfile dependencies, 43 gems now installed.
┃ Use `bundle show [gemname]` to see where a bundled gem is installed.
┃ ✓ bundle install: done
┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
🦄  activating ruby 2.2.4
~/source/measured-rails(dev-yml ✗) dev test
/opt/rubies/2.2.4/bin/ruby -I"lib:test:lib/**/*" -I"/opt/rubies/2.2.4/lib/ruby/2.2.0" "/opt/rubies/2.2.4/lib/ruby/2.2.0/rake/rake_test_loader.rb" "test/active_record_test.rb" "test/validation_test.rb"
-- create_table("things", {:force=>:cascade})
   -> 0.0075s
-- create_table("validated_things", {:force=>:cascade})
   -> 0.0015s
-- initialize_schema_migrations_table()
   -> 0.0229s
Run options: --seed 18970

# Running:

................................................................................

Finished in 0.329020s, 243.1463 runs/s, 556.1972 assertions/s.

80 runs, 183 assertions, 0 failures, 0 errors, 0 skips

[jonathankwok]

👍

[burke]

LGTM!