Add RSpec and Rubocop

Gemfile

@@ -1,4 +1,10 @@
 source 'https://rubygems.org'
+
+gem 'rake'
+
 gem 'github_api'
 gem 'colorize'
-gem 'rake'
+
+group :test do
+    gem 'rubocop'
+end

Rakefile

@@ -1,9 +1,7 @@
-require "rake/testtask"
+require 'rubocop/rake_task'
+require 'rspec/core/rake_task'
 
-task :default => [:test]
+RuboCop::RakeTask.new
+RSpec::Core::RakeTask.new(:rspec)
 
-Rake::TestTask.new do |t|
-  t.verbose = true
-  t.libs.push("demo", "test")
-  t.pattern = "test/**/*_test.rb"
-end
+task :default => [:rubocop, :rspec]