Add default mime type in nginx.conf

conf/nginx.conf

@@ -11,13 +11,16 @@ http {
 
         include mime.types;
         charset utf-8;
+        default_type text/html;
 
         try_files $uri $uri/ $uri.html =404;
 
+        # return `/posts/index.html` from `/posts`
         location = /posts {
             rewrite ^ /posts/ break;
         }
 
+        # redirect requests ending in a forward slash
         location ~ ^/(.+)/$ {
             return 302 /$1;
         }