title: Change extension of webpage but keep search results
body: <p>There is a website that I designed as a standard, static website with pages that I update as required.  All pages are *.html and I have some quite good google rankings.</p>
  
  <p>I'm currently re-writing this site to add a CMS at the backend, this will either change all of the pages to end *.php or to use routes (which is more likely).</p>
  
  <p>How can I change the site but keep existing links and search results?</p>
  
  <p>e.g. If I have a link to <code>www.mySite.com/myPage.html</code>, but in the future this will be <code>www.mySite.com/myPage</code> how do I do this without breaking all links to myPage.html?</p>
  
  <p>My hosting is LAMP at the moment, could this be done by altering the .htaccess file?</p>