Check if irc user already exists before adding

src/freedombone-app-irc

     ZNC_SALT="$(dd if=/dev/urandom bs=16c count=1 | md5sum | awk -F ' ' '{print $1}' | cut -c1-20)"
     new_user_hash=$(echo -n "${new_user_password}${ZNC_SALT}" | sha256sum | awk -F ' ' '{print $1}')
 
+    if grep -q "<User ${new_username}>" /home/znc/.znc/configs/znc.conf; then
+        # user already exists
+        sed -i "s|Hash = .*|Hash = ${new_user_hash}|g" /home/znc/.znc/configs/znc.conf
+        sed -i "s|Salt = .*|Salt = ${ZNC_SALT}|g" /home/znc/.znc/configs/znc.conf
+        return
+    fi
+
     echo "<User ${new_username}>" >> /home/znc/.znc/configs/znc.conf
     echo "    Admin      = ${is_admin}" >> /home/znc/.znc/configs/znc.conf
     echo "    AltNick = ${new_username}_" >> /home/znc/.znc/configs/znc.conf
     dialog --title $"IRC Password" \
            --clear \
            --backtitle $"Freedombone Control Panel" \
-           --passwordbox $"Password for all IRC users, or press Enter for no password" 10 50 2> $data
+           --passwordbox $"Password for all IRC users, or press Enter for no password" 10 60 2> $data
     sel=$?
     case $sel in
         0)