feature #894 Show user by ID (genintho)

This PR was squashed before being merged into the 2.x branch.

Discussion
----------

Revamp of #372 which was abandonned, and following the example of #579


As of 2020, gettting data by ID is still undocumented. I contacted Github support to make sure it could be relied on.


> <img width="691" alt="Screen Shot 2020-07-02 at 10 12 15 PM" src="https://user-images.githubusercontent.com/664857/86434021-2d17f700-bcb1-11ea-9f19-2008ce47412d.png">


------
I have been working with an old application and I have to deal with actions made by user that have changed their login since. The old login are now used by totally different people, which can be problematic.

Commits
-------

5ed46cc Update User.php
5703492 Add unit test
62b43ab Documentation
cdaad05 Remove usage of rawurlencode

doc/users.md

@@ -36,6 +36,13 @@ $user = $client->api('user')->show('KnpLabs');
 
 Returns an array of information about the user.
 
+
+You can also use the User ID, but it will use an undocumented Github API
+
+```php
+$user = $client->api('user')->showById(202732);
+```
+
 ### Update user information
 
 > Requires [authentication](security.md).

lib/Github/Api/User.php

@@ -59,6 +59,21 @@ public function show($username)
         return $this->get('/users/'.rawurlencode($username));
     }
 
+    /**
+     * Get extended information about a user by its id.
+     * Note: at time of writing this is an undocumented feature but GitHub support have advised that it can be relied on.
+     *
+     * @link http://developer.github.com/v3/users/
+     *
+     * @param int $id the id of the user to show
+     *
+     * @return array information about the user
+     */
+    public function showById($id)
+    {
+        return $this->get('/user/'.$id);
+    }
+
     /**
      * Get extended information about a user by its username.
      *

test/Github/Tests/Api/UserTest.php

@@ -20,6 +20,22 @@ public function shouldShowUser()
         $this->assertEquals($expectedArray, $api->show('l3l0'));
     }
 
+    /**
+     * @test
+     */
+    public function shouldShowByIdUser()
+    {
+        $expectedArray = ['id' => 1, 'username' => 'l3l0'];
+
+        $api = $this->getApiMock();
+        $api->expects($this->once())
+            ->method('get')
+            ->with('/user/1')
+            ->will($this->returnValue($expectedArray));
+
+        $this->assertEquals($expectedArray, $api->showById(1));
+    }
+
     /**
      * @test
      */