Homebrew will have installed PHP in /usr/local/bin, do you have this in you $PATH? The order of paths is important - it should be before the path to system php
As @tykus stated as well as it must also be before /use/local/sbin for it to work. Just type in terminal which php to see if the version you are using is coming from /use/local/bin. If it is, then you should be using what you installed via HomeBrew. Also, make sure homebrew linked that version of php. brew link php70. My guess is the linking is the problem or you don't have /usr/local/bin in front of all the other bin paths. It must come before the others.