So I just turned my old Lenovo Z580 into a Android Build Server. And the first problem I faced was that of making it auto connect to the home Wifi everytime I turn it on.

Basically we have to edit the file /etc/network/interfaces and make the contents somewhat like this -

auto wlan0
iface wlan0 inet dhcp 
                wpa-ssid YOUR_WIFI_SSID
                wpa-psk  YOUR_WIFI_PASSWORD

This is assuming you are on a WPA/WPA2 PSK encryption. If you are on WEP, why dear why ? Move to WPA. If you want to affix a permanent static ip address to your server, the contents should rather be like this

auto wlan0
iface wlan0 inet static
				address 192.168.1.111
				netmask 255.255.255.0
				gateway 192.168.1.1
                wpa-ssid YOUR_WIFI_SSID
                wpa-psk  YOUR_WIFI_PASSWORD

This is assuming your router’s ip is 192.168.1.1, and the ip you want to affix the server is 192.168.1.111. Change them to suit your needs.