Remove old docs

Fixes #90

docs/QR_CODES.md

@@ -6,43 +6,4 @@ To do that, add the the following line to your `application.js` file:
 
     //= require devise-otp
 
-You can change this behavior by overriding the `otp_authenticator_token_image` method in your view helper to call `otp_authenticator_token_image_google`:
-
-```ruby
-def otp_authenticator_token_image(resource)
-  otp_authenticator_token_image_google(resource.otp_provisioning_uri)
-end
-```
-
-This will call [Google API](https://github.com/wmlele/devise-otp/tree/master/lib/devise_otp_authenticatable/controllers/helpers.rb#L160) to render the QR code.
-
-If your application is configured to use CSP policies, you'll need to authorize `chart.googleapis.com`. Here's an example with [secure_headers](https://github.com/github/secure_headers)):
-
-```ruby
-config.csp[:img_src] << 'chart.googleapis.com'
-```
-
-A third option consists in installing [jquery-qrcode]https://github.com/jeromeetienne/jquery-qrcode with Yarn or [shakapacker](https://github.com/shakacode/shakapacker) and overriding `otp_authenticator_token_image` to render some HTML :
-
-```ruby
-def otp_authenticator_token_image(resource)
-  tag(:span, data: { toggle: 'qrcode', otp_url: resource.otp_provisioning_uri, width: 192, height: 192, render: 'canvas' })
-end
-```
-The QR code is then rendered by `jquery-qrcode` by setting a JS listener in your `application.js` :
-
-```js
-  $(document).on('turbo:load', function() {
-    return $('[data-toggle=qrcode]').each(function() {
-      var data;
-      data = $(this).data();
-      return $(this).qrcode({
-        text: data['otpUrl'],
-        width: data['width'],
-        height: data['height'],
-        render: data['render']
-      });
-    });
-  });
-```
-This way you don't rely on external services to render the QR codes.
+You can change this behavior by overriding the `otp_authenticator_token_image` method in your view helper.