<system.webServer>
    <rewrite>
      <rules>
        <rule name="Redirect HTTP to HTTPS">
          <match url="(.*)" />
          <conditions>
            <add input="{HTTPS}" pattern="off" ignoreCase="true" />
          </conditions>
          <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="Permanent"  />
        </rule>
      </rules>
    </rewrite>
  </system.webServer>