Fix gzip encoding.

deploy/nginx/main.nginx.conf

@@ -25,6 +25,10 @@ http {
 
     gzip on;
     gzip_vary on;
+    gzip_types    text/plain text/html text/css
+                  application/x-javascript text/xml
+                  application/xml application/xml+rss
+                  text/javascript;
 
     include /etc/nginx/sites-enabled/lb;
     include /etc/nginx/sites-enabled/readthedocs;