added 'Operation Costs in CPU'

- signed-off-by: trimstray <trimstray@gmail.com>

README.md

@@ -425,6 +425,7 @@ performance of any of your sites from across the globe.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://jamielinux.com/docs/openssl-certificate-authority/"><b>OpenSSL Certificate Authority</b></a> - build your own certificate authority (CA) using the OpenSSL command-line tools.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://medium.com/@_bl4de/hidden-directories-and-files-as-a-source-of-sensitive-information-about-web-application-84e5c534e5ad"><b>Hidden directories</b></a> - hidden directories and files as a source of sensitive information about web application.<br>
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+&nbsp;&nbsp;:small_orange_diamond: <a href="http://ithare.com/infographics-operation-costs-in-cpu-clock-cycles/"><b>Operation Costs in CPU</b></a> - an infographics which should help to estimate costs of certain operations in CPU clocks.<br>
 </p>
 
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