set php memory limit

apache2-wordpress.conf

@@ -8,6 +8,11 @@
         Options +FollowSymLinks
         AllowOverride All
         Require all granted
+
+        <IfModule mod_php5.c>
+            php_value memory_limit 64m
+        </IfModule>
+
     </Directory>
 
     # some directories must be protected