Merge pull request #265 from duhanebel/zsh_install_check

Fix a bug that was causing rake to overwrite SHELL settings

Rakefile

@@ -146,9 +146,13 @@ def install_prezto
   run %{ mkdir -p $HOME/.zsh.after }
   run %{ mkdir -p $HOME/.zsh.prompts }
 
+  if ENV[SHELL].include? 'zsh' then
+    puts "Zsh is already configured as your shell of choice. Restart your session to load the new settings"
+  else
     puts "Setting zsh as your default shell"
     run %{ chsh -s /bin/zsh }
   end
+end
 
 def want_to_install? (section)
   if ENV["ASK"]=="true"