title: vim github colorscheme notworking with zsh
body: <p>I am using ubuntu 13.04 with the following configurations</p>
  
  <p>tmux
     vim - github colorscheme
     zsh - default shell</p>
  
  <p>myproblem is when i tried to open a code in vim without tmux it looks fine see below</p>
  
  <p><img src="https://i.stack.imgur.com/VMVWf.png" alt="enter image description here"></p>
  
  <p>but when i use tmux it is breaking the code like below</p>
  
  <p><img src="https://i.stack.imgur.com/KI7zT.png" alt="enter image description here"></p>
  
  <p>am i missing something or do  i need to provide anything?</p>
  
  <p>Thanks in advance</p>