add robots.txt

public/robots.txt

 # See http://www.robotstxt.org/wc/norobots.html for documentation on how to use the robots.txt file
 # See http://www.robotstxt.org/wc/norobots.html for documentation on how to use the robots.txt file
 #
 #
 # To ban all spiders from the entire site uncomment the next two lines:
 # To ban all spiders from the entire site uncomment the next two lines:
-# User-agent: *
-# Disallow: /
+User-agent: *
+Disallow: /