Extra checks to determine if installation is happening on a debian system

src/freedombone

@@ -33,8 +33,27 @@ PROJECT_NAME='freedombone'
 export TEXTDOMAIN=$PROJECT_NAME
 export TEXTDOMAINDIR="/usr/share/locale"
 
+# check that this is installing on an appropriate
+# debian system. If you try to install on an ubuntu
+# base then that will definitely fail
+installing_on_debian=1
 if [ ! -f /usr/bin/apt-get ]; then
-    echo $'You should only run this on a Debian based system'
+    installing_on_debian=
+fi
+
+if [ ! -f /etc/apt/sources.list ]; then
+    installing_on_debian=
+else
+    if ! grep -q 'stretch' /etc/apt/sources.list; then
+        installing_on_debian=
+    fi
+    if ! grep -q 'debian' /etc/apt/sources.list; then
+        installing_on_debian=
+    fi
+fi
+
+if [ ! $installing_on_debian ]; then
+    echo $'You should only run this on a Debian Stretch based system'
     exit 0
 fi