fix: improve code specification (#231)

Dockerfile

@@ -0,0 +1,25 @@
+FROM golang:1.17-rc-buster
+WORKDIR /casdoor
+COPY ./ /casdoor
+RUN go env -w CGO_ENABLED=0 GOPROXY=https://goproxy.io,direct GOOS=linux GOARCH=amd64 \
+    && apt update && apt install sudo \
+    && wget https://nodejs.org/dist/v12.22.0/node-v12.22.0-linux-x64.tar.gz \
+    && sudo tar xf node-v12.22.0-linux-x64.tar.gz \
+    && sudo apt install wait-for-it
+ENV PATH=$PATH:/casdoor/node-v12.22.0-linux-x64/bin
+RUN npm install -g yarn \
+    && cd web \
+    && yarn install \
+    && yarn run build \
+    && rm -rf node_modules \
+    && cd /casdoor \
+    && go build main.go
+FROM alpine:3.7
+COPY --from=0 /casdoor   /
+COPY --from=0 /usr/bin/wait-for-it  /
+RUN set -eux \
+    && sed -i 's/dl-cdn.alpinelinux.org/mirrors.ustc.edu.cn/g' /etc/apk/repositories \
+    && apk update \
+    && apk upgrade \
+    && apk add bash
+CMD ./wait-for-it db:3306 && ./main