fix: update script: non-standard version numbers

store version output in new variable
slice output indexed from beginning instead of end. allowing for custom
build version numbers.

also fix weird spacing from tabs being two spaces wide, sorry :)

scripts/upgrade-server.sh

@@ -7,7 +7,7 @@
 ##	should back them up FIRST.					     ##
 ##									     ##
 ##	This must be run from the web application root directory	     ##
-##		i.e. /var/www/writefreely, and operates under the assumption that you  ##
+##	i.e. /var/www/writefreely, and operates under the assumption that you##
 ##	have not installed the binary `writefreely` in another location.     ##
 ###############################################################################
 #
@@ -35,12 +35,13 @@ url=`curl -s https://api.github.com/repos/writeas/writefreely/releases/latest |
 
 # check current version
 
-current=`./writefreely -v`
+bin_output=`./writefreely -v`
-if [ -z "$current" ]; then
+if [ -z "$bin_output" ]; then
 	exit 1
 fi
 
-echo "Current version is v${current:(-5):5}"
+current=${bin_output:12:5}
+echo "Current version is v$current"
 
 # grab latest version number
 IFS='/'
@@ -51,7 +52,7 @@ echo "Latest release is $latest"
 
 
 IFS='.'
-read -ra cv <<< "${current:(-5):5}"
+read -ra cv <<< "$current"
 read -ra lv <<< "${latest#v}"
 
 IFS=' '