docs(php): add migration guide

Author: damcou

website/docs/clients/migration-guides/index.mdx

@@ -135,6 +135,24 @@ const { taskID } = await client.saveObject({
 await client.waitForTask({ indexName: '<YOUR_INDEX_NAME>', taskID });
 ```
 
+</TabItem>
+<TabItem value="php">
+
+```php
+$client = SearchClient::create(
+    '<YOUR_APP_ID>',
+    '<YOUR_APP_ID>'
+);
+
+$response = $client->saveObject(
+    '<YOUR_INDEX_NAME>',
+    ['title' => "My Algolia Object"],
+);
+
+// Poll the task status with defaults values
+$client->waitForTask('<YOUR_INDEX_NAME>', $response['taskID']);
+```
+
 </TabItem>
 <TabItem value="java">
 
@@ -190,6 +208,27 @@ const { taskID } = await client.operationIndex({
 await client.waitForTask({ indexName: '<SOURCE_INDEX_NAME>', taskID });
 ```
 
+</TabItem>
+<TabItem value="php">
+
+```php
+$client = SearchClient::create(
+    '<YOUR_APP_ID>',
+    '<YOUR_APP_ID>'
+);
+
+$response = $client->operationIndex(
+    '<SOURCE_INDEX_NAME>',
+    [
+        'operation' => 'copy', // 'move'
+        'destination' => '<DESTINATION_INDEX_NAME>'
+    ]
+);
+
+// Poll the task status until it's done
+$client->waitForTask('<SOURCE_INDEX_NAME>', $response['taskID']);
+```
+
 </TabItem>
 <TabItem value="java">
 

website/docs/clients/migration-guides/php.md

@@ -2,4 +2,54 @@
 title: PHP
 ---
 
-WIP
+| Previous             | Latest                                 | Description                                                                                                                                                                                                               |
+| -------------------- | :------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `"algolia/algoliasearch-client-php": "^3.2"`           | `"algolia/algoliasearch-client-php": "^4.0"`  | **During the beta phase**, the clients are available under the package 4.x.x-alpha , you can find a full list [here](https://packagist.org/packages/algolia/algoliasearch-client-php).      |
+| `Algolia\AlgoliaSearch`             | `Algolia\AlgoliaSearch\Api`                         | Exported clients have now the name suffixed by `Api`.                                                                                                                                                                                |
+
+### Usage
+
+To get started, first uninstall the previously added clients.
+
+```bash
+composer remove algolia/algoliasearch-client-php
+```
+
+You can now install the `Algoliasearch` clients.
+
+```bash
+composer require algolia/algoliasearch-client-php "^4.0"
+```
+
+You can continue this guide on [our installation page](/docs/clients/installation).
+
+### Methods targeting an `indexName`
+
+Prior to the `initIndex` removal stated in the [common breaking changes](/docs/clients/migration-guides/#common-breaking-changes), all methods previously available at the `initIndex` level requires the `indexName` to be sent with the query.
+
+```php
+use Algolia\AlgoliaSearch\Api\SearchClient;
+
+$client = SearchClient::create(
+    '<YOUR_APP_ID>',
+    '<YOUR_API_KEY>'
+);
+
+// only query string
+$searchResults = $client->search([
+    'requests' => [
+        ['indexName' => '<YOUR_INDEX_NAME>', 'query' =>'<YOUR_QUERY>'],
+    ],
+]);
+
+$searchResults2 = $client->search([
+    'requests' => [
+        [
+            'indexName' => '<YOUR_INDEX_NAME>', 
+            'query' => '<YOUR_QUERY>',
+            'attributesToRetrieve' => ['firstname', 'lastname'],
+            'hitsPerPage' => 50,
+        ],
+    ],
+]);
+```