Take the Nginx configuration files into account

* Look for and move Nginx configuration files back into the standard
  directory such that the original assemble script will take them into
  account.

assemble

@@ -18,11 +18,31 @@ mv /tmp/src /tmp/src-original
 cd /tmp/src-original/
 /opt/rh/rh-python36/root/usr/bin/mkdocs build --clean --site-dir /tmp/src/
 
+# Move the Nginx-related files back to the standard directory.
+if [ -f ./nginx.conf ]; then
+  echo "---> Moving nginx.conf configuration file..."
+  mv ./nginx.conf /tmp/src/nginx.conf
+fi
+if [ -d ./nginx-cfg ]; then
+  echo "---> Moving nginx configuration files..."
+  mv ./nginx-cfg /tmp/src/nginx-cfg
+fi
+if [ -d ./nginx-default-cfg ]; then
+  echo "---> Moving nginx default server configuration files..."
+  mv ./nginx-default-cfg /tmp/src/nginx-default-cfg
+fi
+if [ -d ./nginx-start ]; then
+  echo "---> Moving nginx start-hook scripts..."
+  mv ./nginx-start /tmp/src/nginx-start
+fi
+
 # Configure nginx to not specify the port in absolute redirects.
-mkdir /tmp/src/nginx-default-cfg/
+if [ ! -f /tmp/src/nginx-default-cfg/redirect.conf ]; then
+mkdir --parents /tmp/src/nginx-default-cfg/
 cat <<EOF> /tmp/src/nginx-default-cfg/redirect.conf
 port_in_redirect off;
 EOF
+fi
 
 # Go back to the current directory.
 cd $cwd