Refactor gemspec

Author: nbulaj

grape_oauth2.gemspec

@@ -6,15 +6,14 @@ Gem::Specification.new do |gem|
   gem.name        = 'grape_oauth2'
   gem.version     = Grape::OAuth2.gem_version
   gem.authors     = ['Nikita Bulai']
-  gem.date        = '2016-05-31'
   gem.email       = ['[email protected]']
   gem.homepage    = 'http://github.com/nbulaj/grape-oauth2'
   gem.summary     = 'Grape OAuth2 provider'
-  gem.description = 'Provides flexible, ORM-agnostic, fully customizable and simple OAuth2 support for Grape APIs'
+  gem.description = 'Flexible, ORM-agnostic, fully customizable and simple OAuth2 provider support for Grape APIs'
   gem.license     = 'MIT'
 
   gem.require_paths = %w[lib]
-  gem.files = `git ls-files`.split($RS)
+  gem.files = `git ls-files`.split($RS) - ['README.md', 'grape_oauth2.png', 'gemfiles', '.travis.yml', '.rubocop.yml']
   gem.test_files = Dir['spec/**/*']
 
   gem.required_ruby_version = '>= 2.2.2'