add simplecov and coveralls for test coverage

help me figure out where I need to look at more closely when making
changes like this

.coveralls.yml

@@ -0,0 +1,2 @@
+service_name: travis-ci
+

emoji_data.gemspec

@@ -21,6 +21,8 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "bundler", "~> 1.3"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "rspec"
+  spec.add_development_dependency 'simplecov', '~> 0.7.1'
+  spec.add_development_dependency 'coveralls', '~> 0.7.0'
 
   spec.required_ruby_version = '>= 1.9.2'
 end

spec/spec_helper.rb

@@ -1,4 +1,15 @@
 require 'rspec'
+require 'simplecov'
+require 'coveralls'
+SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter[
+  SimpleCov::Formatter::HTMLFormatter,
+  Coveralls::SimpleCov::Formatter
+]
+SimpleCov.start do
+  add_filter '/spec'
+  add_filter '/.bundle'
+end
+
 require 'emoji_data'
 include EmojiData