Added an if-statement to see if git is installed

tools/install.sh

@@ -5,7 +5,13 @@ then
 fi
 
 echo "\033[0;34mCloning Oh My Zsh...\033[0m"
-/usr/bin/env git clone https://github.com/robbyrussell/oh-my-zsh.git ~/.oh-my-zsh
+which git > /dev/null
+if [[ $? -eq 0 ]]; then
+  /usr/bin/env git clone https://github.com/robbyrussell/oh-my-zsh.git ~/.oh-my-zsh
+else
+  echo "git not installed"
+  exit
+fi
 
 echo "\033[0;34mLooking for an existing zsh config...\033[0m"
 if [ -f ~/.zshrc ] || [ -h ~/.zshrc ]