修复dockerfile

Author: M3chD09

Dockerfile

@@ -9,9 +9,9 @@ RUN npm run build
 
 FROM golang:latest
 WORKDIR /build
-COPY ./backend ./main.go ./go.sum ./go.mod /build/
-RUN mkdir -p frontend/dist \
-    && go build -ldflags="-w -s" -o Robot_Monitor_Web_linux
-COPY --from=build /app/dist/ /build/frontend/dist
+COPY ./backend /build/backend/
+COPY ./main.go ./go.sum ./go.mod /build/
+RUN go build -ldflags="-w -s" -o Robot_Monitor_Web_linux
+COPY --from=build /app/dist/ /build/frontend/dist/
 
 CMD ./Robot_Monitor_Web_linux $PORT