docs: add failover docs

Author: Cafe137

README.md

@@ -1,6 +1,6 @@
 # Etherproxy
 
-Etherproxy is a JSON-RPC reverse proxy tool designed for caching requests.
+Etherproxy is a robust and lightweight JSON-RPC reverse proxy tool designed for **optimising requests** and **providing failover support**.
 
 ## Usage
 
@@ -16,6 +16,12 @@ The command above starts the JSON-RPC reverse proxy...
 
 Make sure to replace `YOUR_TOKEN` with your actual token.
 
+Supply multiple JSON-RPC `--target` with a comma-separated string:
+
+```
+npx etherproxy --target https://gno.getblock.io/YOUR_TOKEN/mainnet/,https://rpc.gnosischain.com
+```
+
 ## Verify the tool is running
 
 Execute the `curl` command shown below repeatedly and inspect the logs of Etherproxy.
@@ -35,10 +41,16 @@ Cache hit: {"jsonrpc":"2.0","method":"eth_blockNumber","params":[]}
 
 ## Benefits
 
+### Caching
+
 Etherproxy provides several benefits in multi-node scenarios. For instance, requests such as `eth_blockNumber` and `eth_getLogs` are frequently called, sometimes generating many unnecessary requests. By using a reverse proxy, the same requests made within a small time period are grouped together and sent to your JSON-RPC endpoint only once.
 
 As a result, all local nodes receive identical correct responses, and the number of actual requests sent is significantly reduced, which helps to **preserve your request quota** in case of a paid third-party, or **reduce the load** when you run your own Ethereum node.
 
+### Failover
+
+Failover is an essential aspect of maintaining high availability and reliability in network services. Etherproxy's seamless failover capability ensures that if one JSON-RPC endpoint becomes unreachable, the traffic is automatically redirected to another configured endpoint without interruption.
+
 ## Error handling
 
 Whenever an error is thrown, Etherproxy responds with a `503 Service Unavailable` status.