update robots.txt

Dockerfile

@@ -3,3 +3,4 @@ COPY nginx.conf /etc/nginx/nginx.conf
 COPY prayer-generator/license /usr/share/nginx/html/license
 COPY css /usr/share/nginx/html/css
 COPY index.html /usr/share/nginx/html
+COPY robots.txt /usr/share/nginx/html