remove index.html from Dockerfile

Dockerfile

@@ -2,5 +2,4 @@ FROM nginx:alpine
 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