Add udev rules and information on them to the README

Using udev rules is the preferred way of using the software.

90-ratctl.rules

@@ -0,0 +1,26 @@
+# This is a udev rules file. To use it, copy it over to /etc/udev/rules.d/90-ratctl.rules
+# (this might change depending on your distribution).
+
+# Saitek Devices
+
+# Cyborg R.A.T.5
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0cc3", TAG+="uaccess"
+# old Cyborg R.A.T.7
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0ccb", TAG+="uaccess"
+# Cyborg R.A.T.3
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0ccc", TAG+="uaccess"
+# Cyborg R.A.T.9
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0cd7", TAG+="uaccess"
+# Cyborg R.A.T.9
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0cd9", TAG+="uaccess"
+# Cyborg R.A.T.9
+SUBSYSTEM=="usb", ATTRS{idVendor}=="06a3", ATTRS{idProduct}=="0cfa", TAG+="uaccess"
+
+# Mad Catz Devices
+
+# R.A.T 5
+SUBSYSTEM=="usb", ATTRS{idVendor}=="0738", ATTRS{idProduct}=="1705", TAG+="uaccess"
+# R.A.T 9
+SUBSYSTEM=="usb", ATTRS{idVendor}=="0738", ATTRS{idProduct}=="1709", TAG+="uaccess"
+# R.A.T PRO X
+SUBSYSTEM=="usb", ATTRS{idVendor}=="0738", ATTRS{idProduct}=="1718", TAG+="uaccess"

README.md

@@ -27,10 +27,22 @@ great too.
 
 USAGE
 -----
-easiest way :
+The software needs access to your mouse to work properly. There are multiple
+ways to do this.
+
+Easiest (**but insecure**) way :
 ```Shell
 sudo ./ratctl.py
 ```
+Running GUI applications as root is considered dangerous. Thus, the second
+method is preferred:
+copy the `90-ratctl.rules` over to your udev rules directory (usually
+`/etc/udev/rules.d/`, but it might change depending on your distribution).
+
+This file contains rules to make the various R.A.T mice configurable by any
+physically logged-in user. A reboot might be required to apply the changes,
+but shouldn't be necessary. In most cases, `sudo udevadm control --reload`,
+`sudo udevadm trigger`, and replugging your mouse should be enough.
 
 REQUIEREMENTS
 -------------