add F-Droid logo to website

README.md

@@ -11,6 +11,6 @@ A mathematical puzzle game. Try it at https://mwageringel.github.io/everest/
 Building with `make` requires `flutter, curl, rsvg-convert, imagemagick`.
 
 
-APK signing certificate fingerprint (SHA-256):
+APK signing certificate fingerprint (SHA-256) of releases on GitHub:
 
     576bae61b2aba5d1d32a17d373baa36e05beaaefb67d9b47218d004c0e8333d9

website/index.html

@@ -31,7 +31,10 @@ <h1>Android App</h1>
       <p class="w3-text-grey">
         Recommended if you have an Android device (with Android 4.1 or above).
       </p>
-      <a href="https://github.com/mwageringel/everest/releases/download/1.1.2/everest-1.1.2.apk" class="w3-button w3-indigo w3-padding-large w3-margin-top">Download .apk file (18 MB)</a>
+      <a href="https://f-droid.org/packages/io.github.mwageringel.everest/" class="w3-hover-opacity w3-margin-top">
+        <img src="https://fdroid.gitlab.io/artwork/badge/get-it-on.png" alt="Get it on F-Droid" height="80">
+      </a>
+      <!-- <a href="https://github.com/mwageringel/everest/releases/download/1.1.2/everest-1.1.2.apk" class="w3-button w3-indigo w3-padding-large w3-margin-top">Download .apk file (18 MB)</a> -->
     </div>
 
     <div class="w3-col m6 w3-padding-16">