docs: Update slack channel link and improve sharding section clarity (#1437)

fix(docs): Update slack channel link and improve sharding section clarity

Signed-off-by: Fatih Sarhan <[email protected]>

Author: f9n

README.md

@@ -153,4 +153,4 @@ Please see our [CHANGELOG.md](./CHANGELOG.md) for details.
 
 This project is managed by [OpsTree Solutions](http://opstree.com). For any queries or suggestions, you can reach out to us at [[email protected]](mailto:[email protected]).
 
-Join our Slack Channel: [#redis-operator](https://opstree.slack.com/archives/C05MBRB50JG).
+Join our Slack Channel: [#redis-operator](https://join.slack.com/t/opstree/shared_invite/zt-3o8jp35x-UGMU2Cy0WSBk3Lbzqa2wVw).

docs/content/en/docs/Redis Overview/_index.md

@@ -34,20 +34,16 @@ There are two models of setting up cluster in redis:
 - Sharding
 - Replication
 
-Replication is also known as mirroring of data. In replication, all the data get copied from the leader node to the follower node. Sharding is also known as partitioning. It splits up the data by the key to multiple nodes.
+Replication is also known as mirroring of data. In replication, all the data get copied from the leader node to the follower node. 
 
 <div align="center">
     <img src="../../../images/replication.png">
 </div>
 
-<div align="center">
-    <img src="../../../images/sharding.png">
-</div>
-
-In sharding, the keys are getting distributed across both machine A and B. That is, the machine A will hold the 1, 3 key and machine B will hold 2, 4 key:
+Sharding is also known as partitioning. It splits up the data by the key to multiple nodes. In sharding, the keys are getting distributed across both machine A and B. That is, the machine A will hold the 1, 2 key and machine B will hold 3, 4 key.
 
 <div align="center">
-    <img src="https://blog2opstree.files.wordpress.com/2019/06/08d40-1ylzieskl-3rvar6kleoziq.png">
+    <img src="../../../images/sharding.png">
 </div>
 
 ## Redis cluster challenges on Kubernetes