Merge pull request sendgrid#62 from nvzard/nvzard/50

Create USAGE.md

Author: Matt Bernier

README.md

@@ -136,7 +136,7 @@ print $response->body();
 <a name="usage"></a>
 # Usage
 
-- [Example Code](https://github.com/sendgrid/php-http-client/tree/master/examples)
+- [Usage Examples](USAGE.md)
 
 ## Environment Variables 
 

USAGE.md

@@ -0,0 +1,109 @@
+# Usage
+
+Usage examples for SendGrid php-http-client
+
+## Initialization
+
+```
+// If running this outside of this context, use the following include and
+// comment out the two includes below
+// require __DIR__ . '/vendor/autoload.php';
+include(dirname(__DIR__) . '/lib/Client.php');
+// This gets the parent directory, for your current directory use getcwd()
+$path_to_config = dirname(__DIR__);
+$apiKey = getenv('SENDGRID_API_KEY');
+$headers = ['Authorization: Bearer ' . $apiKey];
+$client = new SendGrid\Client('https://api.sendgrid.com', $headers, '/v3');
+```
+
+## Table of Contents
+
+- [GET](#get)
+- [DELETE](#delete)
+- [POST](#post)
+- [PUT](#put)
+- [PATCH](#patch)
+
+<a name="get"></a>
+## GET
+
+#### GET Collection
+
+```
+$query_params = ['limit' => 100, 'offset' => 0];
+$request_headers = ['X-Mock: 200'];
+$response = $client->api_keys()->get(null, $query_params, $request_headers);
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+```
+
+#### GET with auto retry on rate limit
+
+```
+$query_params = ['limit' => 100, 'offset' => 0];
+$request_headers = ['X-Mock: 200'];
+$retryOnLimit = true;
+$response = $client->api_keys()->get(null, $query_params, $request_headers, $retryOnLimit);
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+```
+
+<a name="delete"></a>
+## DELETE
+
+```
+$response = $client->api_keys()->_($api_key_id)->delete();
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+```
+
+<a name="post"></a>
+## POST
+
+```
+$request_body = [
+    'name' => 'My PHP API Key',
+    'scopes' => [
+        'mail.send',
+        'alerts.create',
+        'alerts.read'
+    ]
+];
+$response = $client->api_keys()->post($request_body);
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+$response_body = json_decode($response->body());
+$api_key_id = $response_body->api_key_id;
+```
+<a name="put"></a>
+## PUT
+
+```
+$request_body = [
+    'name' => 'A New Hope',
+    'scopes' => [
+        'user.profile.read',
+        'user.profile.update'
+    ]
+];
+$response = $client->api_keys()->_($api_key_id)->put($request_body);
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+```
+<a name="patch"></a>
+## PATCH
+
+```
+$request_body = [
+    'name' => 'A New Hope'
+];
+$response = $client->api_keys()->_($api_key_id)->patch($request_body);
+echo $response->statusCode();
+echo $response->body();
+echo $response->headers();
+```