Question: How can I add an icon to my Rails application (to show in tabs when opened in a browser, etc.)?

Answer: 
You can use [Favicon Rails](http://apidock.com/rails/ActionView/Helpers/AssetTagHelper/favicon_link_tag) helper:

```
<%= favicon_link_tag %>

```

Or if you want another image than favicon.ico

```
<%= favicon_link_tag 'another_image.ico' %>

```
After reading and trying all this answers without success I ended up doing this

1. Add a file **favicon.png** to your **public/assets** folder
2. In your **$/app/views/layouts/application.html.erb** modify the content of the `<head>` tag adding this `<link rel="icon" type="image/png" href="/assets/favicon.png">`

No need to change the web\_server configuration file (nginx, apache, etc) no need to precompile the assets. 

Just stop and run/debug your web site, clear the cache from your browser and reopen the page. It should work