Update readme.md (#68)

@Poussinou cheers for that!

readme.md

@@ -17,9 +17,14 @@ The javadoc should provide all information needed to understand the methods, but
 
 ### Sample app
 
-The sample app is published on Google play to allow you to quickly and easier test the library. Enjoy! And please do feedback to us if your tests produce different results. 
+The sample app is published on Google Play & F-Droid to allow you to quickly and easier test the library. Enjoy! And please do feedback to us if your tests produce different results. 
 
-<a href="https://play.google.com/store/apps/details?id=com.stealthcotper.networktools&utm_source=global_co&utm_medium=prtnr&utm_content=Mar2515&utm_campaign=PartBadge&pcampaignid=MKT-Other-global-all-co-prtnr-py-PartBadge-Mar2515-1"><img alt="Get it on Google Play" src="https://play.google.com/intl/en_us/badges/images/generic/en-play-badge.png" width="150"/></a>
+[<img src="https://fdroid.gitlab.io/artwork/badge/get-it-on.png"
+     alt="Get it on F-Droid"
+     height="70">](https://f-droid.org/packages/com.stealthcotper.networktools/)
+[<img src="https://play.google.com/intl/en_us/badges/images/generic/en-play-badge.png"
+     alt="Get it on Google Play"
+     height="70">](https://play.google.com/store/apps/details?id=com.stealthcotper.networktools)
 
 ## Usage
 
@@ -140,7 +145,6 @@ Other useful methods:
 
 It's a standard gradle project.
 
-
 # Contributing
 
 I welcome pull requests, issues and feedback.
@@ -150,4 +154,3 @@ I welcome pull requests, issues and feedback.
 - Commit your changes (git commit -am 'Added some feature')
 - Push to the branch (git push origin my-new-feature)
 - Create new Pull Request
-