For most people it takes just four steps to update your Raspberry Pi SD card to work in the Raspberry Pi 2. (And it’ll still work in your Rpi1.)
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
sudo apt-get install raspberrypi-ui-mods
There are a few additional instructions if you’re running NOOBs (see source) but if you’re not. You’re all done.
Source: The Pi Hut.