Revert "Removed support for NetGuard hosts file"

This reverts commit 719fa4caa3.

ADBLOCKING.md

@@ -9,6 +9,7 @@ Instructions:
 * Import or download [a hosts file](https://en.wikipedia.org/wiki/Hosts_(file)) using the NetGuard backup settings
 * Disable browser compression (Chrome: three dot menu > Settings > Data Saver > Off)
 * Wait 10 minutes to let the Android DNS cache time out
+* Test if it works by opening [this page](http://www.netguard.me/test)
 * Enjoy ad blocking, but don't forget to support application developers in other ways
 
 <br />
@@ -17,7 +18,7 @@ Note that:
 
 * applications, like the browser, may cache data, so you might need to clear caches
 * applications, browsers mostly, that have a *"data saver"* like feature that proxies requests through their servers (eg. Opera w/ Turbo, Opera Max app, Puffin, Chrome w/ data saver, UC Browser, Yandex w/ Turbo, Apus Browser, KK Browser, Onavo Extend, Maxthon) will not have ads blocked as NetGuard can't even see those domain requests
-* which hosts (ad servers) will be blocked depends on the hosts file being used
+* the test page only works using the hosts file downloaded from [here](https://www.netguard.me/hosts) (the default)
 * YouTube ads are not domain based and cannot be blocked
 * NetGuard does not use the IP adresses in the hosts file, because it doesn't route blocked domains to localhost
 * NetGuard does not concatenate hosts files, so you will have to use a source which does this for you or do it yourself
@@ -33,6 +34,15 @@ The NetGuard version from GitHub:
 
 <br />
 
+Which hosts (ad servers) will be blocked depends on the hosts file being used.
+NetGuard provides the [StevenBlack hosts file](https://github.com/StevenBlack/hosts) download with the following additions:
+
+* reports.crashlytics.com
+* settings.crashlytics.com
+* e.crashlytics.com
+
+<br />
+
 Automation:
 
 You can automatically download a hosts file by sending this service intent with your favorite automation tool, like Tasker: