Make it easier to run this script if preconditions are missing

update-app.sh

@@ -3,6 +3,21 @@
 # fail script if one command fails
 set -e
 
+# check if unprivileged
+if [ $(id -u) -eq 0]
+  then
+	echo "Please do not run this script as root."
+	exit 0
+fi
+
+# check file permissions
+if [[ -w ~/wp-content/plugins ]]
+  then
+	echo "Missing file permissions. To fix this, run this command as root:"
+	echo "  chown $USER /home/$USER/wp-content/plugins -R"
+	exit 0
+fi
+
 # we need at least one argument
 if [ $# -eq 0 ]
   then