Update README.md

Author: Roël Couwenberg

README.md

@@ -1,2 +1,52 @@
 # DirectApi
-An API wrapper for the DirectAdmin API.
+DirectApi is a wrapper for the DirectAdmin API.
+
+## Installation
+Use the package manager [composer](https://getcomposer.org/) to install DirectApi.
+```bash
+composer require avametix/directapi
+```
+
+## Usage
+
+```php
+use Avametix\DirectApi;
+
+// Create a new DirectApi instance logged in with user "username" and password "password"
+$directapi = new DirectApi(
+    'da.domain.io',
+    'username',
+    'password',
+    'https',
+    2222
+);
+
+// Get user domains
+$domains = $directapi->get("SHOW_DOMAINS");
+
+if ($domains === false) {
+    die(
+        "Something went wrong fetching domains for username,<br/>
+        are you using the right password?"
+        );
+}
+
+foreach ($domain in $domains) {
+    echo $domain . "<br/>";
+}
+
+// Log-in as user via reseller (directapi is initialised with reseller or admin login)
+$directapi->login_as('clientuser');
+
+// ...
+
+$directapi->logout();
+```
+
+All DirectAdmin API commands can be found in the [DirectAdmin documentation](https://www.directadmin.com/api.php).
+
+## Contributing
+Contributions are primarily made by members of [Avametix](https://avametix.com), however pull requests are welcome. Planning a major change? Please open an issue first and discuss your changes.
+
+## License
+[GNU General Public License](https://choosealicense.com/licenses/gpl-3.0/)