Add "Lift the Elephant" book to docs/books

The author has in the email thread granted permission to use the
cover art in our listing.

Author: Daniel Gustafsson <daniel@yesql.se>
Reported-by: Alex Yarotsky <yarotsky.alex@gmail.com>
Discussion: https://postgr.es/m/CAFf0AzyBTHmd3m+NaQ1AVMOq2Op5Rg5TzFReJLzJML5QipWE8g@mail.gmail.com

Author: danielgustafsson

media/img/docs/books/lift_the_elephant.png

@@ -41,6 +41,21 @@ <h1>Books <i class="fas fa-book"></i></h1>
            <strong>Published</strong>: June 2025
         </td>
       </tr>
+      <tr>
+        <td>
+            <a href="https://leanpub.com/lift-the-elephant/">
+              <img src="/media/img/docs/books/lift_the_elephant.png"
+                   alt="Lift the Elephant: Scaling PostgreSQL Beyond Query Optimization" /></a>
+        </td>
+        <td>
+           <strong>Title</strong>: Lift the Elephant: Scaling PostgreSQL Beyond Query Optimization<br />
+           <strong>Author</strong>: Alex Yarotsky<br />
+           <strong>Language</strong>: English<br />
+           <strong>Current version at publication</strong>: 17<br />
+           <strong>Format</strong>: eBook<br />
+           <strong>Published</strong>: February 2025
+        </td>
+      </tr>
       <tr>
         <td>
             <a href="https://www.amazon.com/Introduction-PostgreSQL-data-professional-Ryan/dp/1036902374">