allow duplicate links

It’s a common practice to link the title and the cover image both to the same location.

Removes whitelist which was only there because duplicate links were causing build errors.

.gitignore

@@ -0,0 +1 @@
+ab*.json

.travis.yml

@@ -4,6 +4,6 @@ rvm:
 before_script:
   - gem install awesome_bot
 script:
-  - awesome_bot README.md --allow-redirect --white-list golang-book,gopl.io,0636920046516,manning.com/books/learn-go,jannewmarch,codegangsta,creativecommons,gobyexample,Ketelsen-GOinA.jpg,amazon,amzn
+  - awesome_bot README.md --allow-dupe --allow-redirect
 notifications:
   email: false