Update README. Add section for post-deployment search API calls.

README.md

@@ -82,6 +82,38 @@ const client = await search()
 
 Now `client` is an instance of the [OpenSearch JavaScript client](https://opensearch.org/docs/latest/clients/javascript/index/), and you can call any client method on it — for example, [`client.index.create()`](https://opensearch.org/docs/latest/clients/javascript/index/#creating-an-index), [`client.index()`](https://opensearch.org/docs/latest/clients/javascript/index/#indexing-a-document), or [`client.search()`](https://opensearch.org/docs/latest/clients/javascript/index/#searching-for-documents).
 
+## Making post-deployment requests to OpenSearch or ElasticSearch from your application
+
+If you would like to make requests to automatically configure your OpenSearch or ElasticSearch instance after deployment, you may optionally add a postdeploy-search.js file in the root directory of your Architect project. This file should export a function that takes no arguments as its default export. Be sure to connect with your OpenSearch or ElasticSearch instance before making your requests.
+
+Here's an sample postdeploy-search.js file for making requests to OpenSearch:
+
+```ts
+import { search } from '@nasa-gcn/architect-functions-search'
+
+export default async function () {
+  const client = await search()
+
+  //Set cluster settings
+  const cluster_settings_request = {
+    method: 'PUT',
+    path: '/_cluster/settings',
+    body: {
+      persistent: {
+        cluster.max_shards_per_node: '500',
+      },
+    },
+  }
+
+  try {
+    await client.transport.request(cluster_settings_request)
+  } catch (e) {
+    console.log('Error: ', e)
+    return
+  }
+}
+```
+
 ## Advanced usage from your application
 
 If you would like to manually connect to OpenSearch from your application, then you will need to sign your requests using [AWS SIG4](https://docs.aws.amazon.com/AmazonS3/latest/API/sig-v4-authenticating-requests.html); the OpenSearch client library provides the [`AwsSigv4Signer`](https://opensearch.org/docs/latest/clients/javascript/index/#authenticating-with-amazon-opensearch-service--aws-sigv4) helper to automate this.