feat(ci): setup travis configuration

.travis.yml

@@ -0,0 +1,10 @@
+language: ruby
+cache: bundler
+rvm:
+  - 2.0
+  - 2.1
+  - 2.2
+  - 2.3
+gemfile:
+  - spec/gemfiles/middleman.3.3.gemfile
+  - spec/gemfiles/middleman.4.0.gemfile

spec/gemfiles/middleman.4.0.gemfile

@@ -3,4 +3,4 @@ loader_gemfile.sub! "gemspec", 'gemspec path: "../../"'
 loader_gemfile.sub! "path: 'spec/", "path: '../../spec/"
 eval loader_gemfile, binding
 
-gem 'middleman', git: 'git@github.com:middleman/middleman.git'
+gem 'middleman', '~> 4.0'

tasks/specs.rake

@@ -38,10 +38,18 @@ namespace :specs do
     end
   end
 
+  desc "run middleman specs w/ CI gemfile"
+  task :ci do
+    system 'bundle exec rspec spec/'
+  end
 end
 
 desc "run all specs on ruby #{RUBY_VERSION}"
 task :specs do
-  Rake::Task['specs:stable'].invoke
-  Rake::Task['specs:head'].invoke
+  if ENV['CI']
+    Rake::Task['specs:ci'].invoke
+  else
+    Rake::Task['specs:stable'].invoke
+    Rake::Task['specs:head'].invoke
+  end
 end