Add Yard for documentation

.yardopts

@@ -0,0 +1,3 @@
+--readme README.md
+--charset utf-8
+'lib/**/*.rb' - '*.md'

Gemfile

@@ -7,6 +7,9 @@ gemspec
 group :development do
   gem 'rake'
 
+  # Documentation:
+  gem 'yard'
+
   # Testing libraries:
   gem 'rspec'
   gem 'vcr'
@@ -20,6 +23,7 @@ group :development do
   gem 'guard'
   gem 'guard-bundler'
   gem 'guard-rspec'
+  gem 'guard-yard'
   gem 'rb-fsevent'
   gem 'rb-readline'
   gem 'fuubar'

Guardfile

@@ -9,3 +9,8 @@ guard 'rspec', version: 2, cli: '--format Fuubar --colour' do
   watch(%r{^lib/(.+)\.rb})     { |m| "spec/#{m[1]}_spec.rb" }
   watch('spec/spec_helper.rb') { "spec" }
 end
+
+guard 'yard', stdout: '/dev/null', stderr: '/dev/null' do
+  watch('README.md')
+  watch(%r{lib/.+\.rb})
+end