[Gemfile] replaced comments for local gems with ENV

Gemfile

@@ -6,13 +6,15 @@ end
 gemspec
 
 group :development do
-  gem "cocoapods-core",       :git => "git://github.com/CocoaPods/Core.git"
-  gem "xcodeproj",            :git => "git://github.com/CocoaPods/Xcodeproj.git"
-  gem "cocoapods-downloader", :git => "git://github.com/CocoaPods/cocoapods-downloader"
-
-  # gem "cocoapods-core",       :path => "../Core"
-  # gem "xcodeproj",            :path => "../Xcodeproj"
-  # gem "cocoapods-downloader", :path => "../cocoapods-downloader"
+  if ENV['COCOA_PODS_DEPENDENCIES'] == 'local'
+    gem 'cocoapods-core',       :path => '../Core'
+    gem 'xcodeproj',            :path => '../Xcodeproj'
+    gem 'cocoapods-downloader', :path => '../cocoapods-downloader'
+  else
+    gem 'cocoapods-core',       :git => "git://github.com/CocoaPods/Core.git"
+    gem 'xcodeproj',            :git => "git://github.com/CocoaPods/Xcodeproj.git"
+    gem 'cocoapods-downloader', :git => "git://github.com/CocoaPods/cocoapods-downloader.git"
+  end
 
   gem "mocha"
   gem "bacon"
@@ -35,3 +37,4 @@ group :documentation do
   gem 'github-markup'
   gem 'pygments.rb'
 end
+