docs(README): update README

README.md

@@ -1,8 +1,22 @@
 ember-localized-model
 ==============================================================================
 
-[Short description of the addon.]
+Handle mutli-lang model fields where your JSON:API returns a dictionary / object
+with all languages present.
 
+__Example:__
+```
+{
+  id: "1",
+  type: "books",
+  attributes: {
+    name: {
+      "de": "Der Name des Windes",
+      "en": "The name of the wind"
+    } 
+  }
+}
+```
 
 Compatibility
 ------------------------------------------------------------------------------
@@ -23,8 +37,52 @@ ember install ember-localized-model
 Usage
 ------------------------------------------------------------------------------
 
-[Longer description of how to use the addon in apps.]
+#### First steps
+
+> You need `ember-intl` for this addon to work: `ember install ember-intl`
+
+To use this addon, first you need to import and extend your model from `LocalizedModel`:
+```js
+import { LocalizedModel  } from "ember-localized-model";
+
+export default class YourModel extends LocalizedModel {}
+```
+
+To serialize the multi-lang field correctly you also need to add a serializer:
+```js
+import { LocalizedSerializer } from "ember-localized-model";
+
+export default class YourModelSerializer extends LocalizedSerializer {}
+```
+Once this is done, you can start adding your localized field via the `@localizedAttr` decorator:
+```js
+import { LocalizedModel, localizedAttr } from "ember-localized-model";
+
+export default class YourModel extends LocalizedModel {
+  @localizedAttr firstName;
+  @localizedAttr lastName;
+}
+```
+
+#### Accessing the fields value
+To read the model field you can simply use `yourModel.firstName`.
+
+The locale the field displays depends on your `intl.primaryLocale`. You can
+change your `primaryLocale` to display the model field in another locale.
 
+If you want to switch locale for only one specific model, you can set
+`yourModel.localizedFieldLocale` to the desired locale. 
+
+If you want to access the raw data as sent by the backend, you can use
+`yourModel.getUnlocalizedField("firstName")`. This will return the raw data. 
+
+For example: 
+```
+{
+  "de": "Johan",
+  "en": "John"
+}
+```
 
 Contributing
 ------------------------------------------------------------------------------
@@ -35,4 +93,4 @@ See the [Contributing](CONTRIBUTING.md) guide for details.
 License
 ------------------------------------------------------------------------------
 
-This project is licensed under the [MIT License](LICENSE.md).
+This project is licensed under the [GPL-3.0 License](LICENSE).