Merge pull request #255 from aminecmi/fdroid/build

A fix for #254.

app/build.gradle

@@ -2,7 +2,7 @@ buildscript {
 }
 
 def gitVersion() {
-    def process = "git for-each-ref refs/tags --sort=-authordate --format='%(refname:short)' --count=1".execute()
+    def process = 'git describe --contains HEAD'.execute()
     return process.text.replaceAll("'", "").substring(1).replaceAll("\\.", "").trim()
 }