fix: url option for iOS, add docs (#43)

Detox.js

@@ -84,6 +84,7 @@ let waitFor;
  * * `reloadReactNative` - should be enabled for React Native applications.
  * * `reuse` - reuse application for tests. By default, Detox reinstalls and relaunches app.
  * * `registerGlobals` - (default: true) Register Detox helper functions `by`, `element`, `expect`, `waitFor` globally.
+ * * `url` - URL to open via deep-link each time the app is launched (android) or immediately afterwards (iOS). Useful for opening a bundle URL at the beginning of tests when working with Expo.
  *
  */
 class Detox extends Helper {
@@ -190,6 +191,10 @@ class Detox extends Helper {
       await this.device.reloadReactNative();
     } else {
       await this.device.launchApp({ newInstance: true, url: this.options.url });
+
+      if (this.device.getPlatform() === 'ios' && this.options.url) {
+        await this.device.openURL({ url: this.options.url });
+      }
     }
   }