make shell use user-installed binaries before system ones

Alerted of this by mac homebrew doctor

zsh/zshenv

@@ -12,7 +12,7 @@ export LESS='-eirMX'
 export EDITOR='vim'
 
 ## paths
-export PATH=/usr/sbin:/usr/bin:/usr/local/bin:~/bin:$PATH
+export PATH=/usr/local/bin:~/bin:/usr/sbin:/usr/bin:$PATH
 export PATH=$HOME/.rvm/bin:$PATH
 
 # Add /usr/local manpages