'Backports' Debian repo not appended to pre-existing sources file instead of creating a new one

post-inst.sh

@@ -115,7 +115,9 @@ Pin: release n=${UBUNTU_VERSION_CODENAME}-backports
 Pin-Priority: -1
 EOF
 elif [[ "${ID}" == 'debian' ]]; then
-	cat << EOF | tee /etc/apt/sources.list.d/backports.sources &> /dev/null
+	cat << EOF | tee --append /etc/apt/sources.list.d/${VERSION_CODENAME}.sources &> /dev/null
+
+# ${VERSION_CODENAME^} Backports
 Enabled:		yes
 Types:			deb deb-src
 URIs:			http://deb.debian.org/debian/