Using apt-get install in chroot

Question

I used debootstrap to create a chroot environment:

sudo debootstrap trusty trusty/
sudo chroot trusty

I'm using chroot. but command apt-get doesn't work:

I have no name!@user:/# apt-get install python
bash: apt-get: command not found

How can i use apt-get in chroot. Or, how can i install an specific application (for instance python), for chroot, so chroot can use it?

I'm using Ubuntu 14.04.

Thanks in advance.