Adds Rancher to Adopters.md (#590)

Co-authored-by: Ferenc HERNADI <ferenc.hernadi@gmail.com>
Co-authored-by: Peter Wilcsinszky <peterwilcsinszky@gmail.com>

ADOPTERS.md

@@ -8,4 +8,5 @@ This is a list of production adopters of Logging Operator:
 |[hipages](https://hipages.com.au)|E-commerce|
 |[Code Factory](https://codefactory.hu)|Software Development/Consultancy|
 |[Flexera](https://www.flexera.com/) | Optimizing your IT assets from on-premises to the cloud |
+|[Rancher](https://rancher.com/docs/rancher/v2.x/en/logging/#changes-in-rancher-v2-5)|As of Rancher 2.5, Rancher’s logging feature is powered by the Banzai Cloud Logging operator instead of Rancher’s in-house logging solution|
 |staffscale.io | Enterprise Resource Planning |