Provide easy way to pass git owner/branch while testing

extras/installer.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-ORIGIN_REPO="https://github.com/mrworf/plexupdate"
+ORIGIN_REPO="https://github.com/${GIT_OWNER:-mrworf}/plexupdate"
 FULL_PATH="/opt/plexupdate"
 CONFIGFILE="/etc/plexupdate.conf"
 CONFIGCRON="/etc/plexupdate.cron.conf"
@@ -153,7 +153,7 @@ configure_plexupdate() {
 	fi
 	if yesno $default; then
 		PUBLIC=no
-		source get-plex-token
+		source "${FULL_PATH}/get-plex-token"
 		getPlexToken
 		if [ -z "$TOKEN" ]; then
 			abort "Failed to retrieve Plex token, please try again."

plexupdate.sh

@@ -82,10 +82,7 @@ URL_DOWNLOAD='https://plex.tv/api/downloads/1.json?channel=plexpass'
 URL_DOWNLOAD_PUBLIC='https://plex.tv/api/downloads/1.json'
 
 #URL for new version check
-UPSTREAM_GIT_URL='https://raw.githubusercontent.com/mrworf/plexupdate/master/plexupdate.sh'
-
-#Branch to fetch updates from
-BRANCHNAME="master"
+UPSTREAM_GIT_URL="https://raw.githubusercontent.com/${GIT_OWNER:-mrworf}/plexupdate/${BRANCHNAME:-master}/plexupdate.sh"
 
 #Files "owned" by plexupdate, for autoupdate
 PLEXUPDATE_FILES="plexupdate.sh extras/installer.sh extras/cronwrapper"