Add Retool as a new premium sponsor (#6977)

Author: tomchristie

README.md

@@ -26,8 +26,9 @@ The initial aim is to provide a single full-time position on REST framework.
 [![][kloudless-img]][kloudless-url]
 [![][esg-img]][esg-url]
 [![][lightson-img]][lightson-url]
+[![][retool-img]][retool-url]
 
-Many thanks to all our [wonderful sponsors][sponsors], and in particular to our premium backers, [Sentry][sentry-url], [Stream][stream-url], [Rollbar][rollbar-url], [Cadre][cadre-url], [Kloudless][kloudless-url], [ESG][esg-url], and [Lights On Software][lightson-url].
+Many thanks to all our [wonderful sponsors][sponsors], and in particular to our premium backers, [Sentry][sentry-url], [Stream][stream-url], [Rollbar][rollbar-url], [Cadre][cadre-url], [Kloudless][kloudless-url], [ESG][esg-url], [Lights On Software][lightson-url], and [Retool][retool-url].
 
 ---
 
@@ -199,6 +200,7 @@ Please see the [security policy][security-policy].
 [kloudless-img]: https://raw.githubusercontent.com/encode/django-rest-framework/master/docs/img/premium/kloudless-readme.png
 [esg-img]: https://raw.githubusercontent.com/encode/django-rest-framework/master/docs/img/premium/esg-readme.png
 [lightson-img]: https://raw.githubusercontent.com/encode/django-rest-framework/master/docs/img/premium/lightson-readme.png
+[retool-img]: https://raw.githubusercontent.com/encode/django-rest-framework/master/docs/img/premium/retool-readme.png
 
 [sentry-url]: https://getsentry.com/welcome/
 [stream-url]: https://getstream.io/try-the-api/?utm_source=drf&utm_medium=banner&utm_campaign=drf
@@ -207,6 +209,7 @@ Please see the [security policy][security-policy].
 [kloudless-url]: https://hubs.ly/H0f30Lf0
 [esg-url]: https://software.esg-usa.com/
 [lightson-url]: https://lightsonsoftware.com
+[lightson-url]: https://retool.com/?utm_source=djangorest&utm_medium=sponsorship
 
 [oauth1-section]: https://www.django-rest-framework.org/api-guide/authentication/#django-rest-framework-oauth
 [oauth2-section]: https://www.django-rest-framework.org/api-guide/authentication/#django-oauth-toolkit

docs/img/premium/retool-readme.png

@@ -73,10 +73,11 @@ continued development by **[signing up for a paid plan][funding]**.
     <li><a href="https://cadre.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/cadre.png)">Cadre</a></li>
     <li><a href="https://hubs.ly/H0f30Lf0" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/kloudless-plus-text.png)">Kloudless</a></li>
     <li><a href="https://lightsonsoftware.com" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/lightson-dark.png)">Lights On Software</a></li>
+    <li><a href="https://retool.com/?utm_source=djangorest&utm_medium=sponsorship" style="background-image: url(https://fund-rest-framework.s3.amazonaws.com/retool-sidebar.png)">Retool</a></li>
 </ul>
 <div style="clear: both; padding-bottom: 20px;"></div>
 
-*Many thanks to all our [wonderful sponsors][sponsors], and in particular to our premium backers, [Sentry](https://getsentry.com/welcome/), [Stream](https://getstream.io/?utm_source=drf&utm_medium=banner&utm_campaign=drf), [ESG](https://software.esg-usa.com/), [Rollbar](https://rollbar.com/?utm_source=django&utm_medium=sponsorship&utm_campaign=freetrial), [Cadre](https://cadre.com), [Kloudless](https://hubs.ly/H0f30Lf0), and [Lights On Software](https://lightsonsoftware.com).*
+*Many thanks to all our [wonderful sponsors][sponsors], and in particular to our premium backers, [Sentry](https://getsentry.com/welcome/), [Stream](https://getstream.io/?utm_source=drf&utm_medium=banner&utm_campaign=drf), [ESG](https://software.esg-usa.com/), [Rollbar](https://rollbar.com/?utm_source=django&utm_medium=sponsorship&utm_campaign=freetrial), [Cadre](https://cadre.com), [Kloudless](https://hubs.ly/H0f30Lf0), [Lights On Software](https://lightsonsoftware.com), and [Retool](https://retool.com/?utm_source=djangorest&utm_medium=sponsorship).*
 
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