Add link

README.md

@@ -905,6 +905,7 @@ Various resources, such as books, websites and articles, for improving your PHP
 * [PHP Sucks! But I Like It!](https://blog.ircmaxell.com/2012/04/php-sucks-but-i-like-it.html) - An article about the pros and cons of PHP.
 * [Preventing CSRF Attacks](https://blog.ircmaxell.com/2013/02/preventing-csrf-attacks.html) - An article on preventing CSRF attacks.
 * [Seven Ways to Screw Up BCrypt](https://blog.ircmaxell.com/2012/12/seven-ways-to-screw-up-bcrypt.html) - An article about correct BCrypt implementation.
+* [The 2018 Guide to Building Secure PHP Software](https://paragonie.com/blog/2017/12/2018-guide-building-secure-php-software) - A guide to building secure PHP software.
 * [Use Env](https://seancoates.com/blogs/use-env/) - An article about using the unix environment helper.
 
 ### PHP Internals Reading