Add documentation for the manual installation method to the README.

Author: orlitzky

README.markdown

@@ -55,20 +55,65 @@ A possible solution to this would be to create an extra APIs implementing the mi
 
 ## Install
 
-Through [composer](http://getcomposer.org/download/), simply run :
+### Composer
+
+[Composer](http://getcomposer.org/download/) users can simply run:
 
 ```bash
 $ php composer.phar require kbsali/redmine-api:~1.0
 ```
 
+at the root of their projects. To utilize the library, include
+Composer's `vendor/autoload.php` in the scripts that will use the
+`Redmine` classes.
+
+For example,
+
+```php
+<?php
+// This file is generated by Composer
+require_once 'vendor/autoload.php';
+$client = new Redmine\Client('http://redmine.example.com', 'username', 'password');
+```
+
+### Manual
+
+It is also possible to install the library oneself, either locally to
+a project or globally; say, in `/usr/share/php`.
+
+First, download and extract the library somewhere. For example, the
+following steps extract v1.5.1 of the library into the
+`vendor/php-redmine-api-1.5.1` directory:
+
+```bash
+$ mkdir vendor
+$ wget -q https://github.com/kbsali/php-redmine-api/archive/v1.5.1.tar.gz
+$ tar -xf v1.5.1.tar.gz -C vendor/
+$ rm v1.5.1.tar.gz
+```
+
+Now, in any scripts that will use the `Redmine` classes, include the
+`lib/autoload.php` file from the php-redmine-api directory. For
+example,
+
+```php
+<?php
+// This file ships with php-redmine-api
+require 'vendor/php-redmine-api-1.5.1/lib/autoload.php';
+$client = new Redmine\Client('http://redmine.example.com', 'username', 'password');
+```
+
 ## Basic usage of `php-redmine-api` client
 
 ```php
 <?php
 
-// This file is generated by Composer
+// For Composer users (this file is generated by Composer)
 require_once 'vendor/autoload.php';
 
+// Or if you've installed the library manually, use this instead.
+// require 'vendor/php-redmine-api-x.y.z/lib/autoload.php';
+
 $client = new Redmine\Client('http://redmine.example.com', 'API_ACCESS_KEY');
 //-- OR --
 $client = new Redmine\Client('http://redmine.example.com', 'username', 'password');
@@ -87,7 +132,7 @@ $client->api('issue')->all([
 ]);
 ```
 
-see `example.php`
+See `example.php` for further examples.
 
 ## User Impersonation