How to add .patch

Noob question here: How do I add this patch to activemerchant?

http://jadedpixel.lighthouseapp.com/attachments/24184/paymentech_gateway.patch

Noob question here: How do I add this patch to activemerchant?

Lighthouse - Beautifully Simple Issue Tracking

cd to the src code you want to patch then do something like:

wget -O - Lighthouse - Beautifully Simple Issue Tracking

patch -p1

http://www.google.com/search?q=how+to+apply+a+patch