Update readme with user information

Author: jaapio

README.md

@@ -1,2 +1,26 @@
-# shim
-phpDocumentor phar as composer package
+# phpDocumentor phar distribution.
+
+This package allows users to install phpDocumentor via composer.
+Using the distributed phar's from the [phpDocumentor main repo](https://github.com/phpDocumentor/phpDocumentor).
+This package only provides an installer.
+New tags are created when a new version of phpDocumentor is released.
+If you want to use a bleeding edge version of phpDocumentor please consult the main repo.
+
+## Usage
+
+Add phpdocumentor to your project.
+
+```
+composer require --dev phpdocumentor/shim:3^
+```
+
+phpDocumentor phar will be downloaded and adding into your projects `bin` directory.
+Which is `vendor/bin` by default.
+
+From now, you can follow the normal flow to use phpDocumentor.
+For more information about using phpDocumentor please read our [docs](https://docs.phpdoc.org/latest).
+
+## Report issues
+
+If you have any issues using phpDocumentor please report bugs in the [main repo](https://github.com/phpDocumentor/phpDocumentor/issues)
+