more features and fix database/mysql:jwt example

_examples/auth/basicauth/database/Dockerfile

@@ -0,0 +1,18 @@
+# docker build -t myapp . 
+# docker run --rm -it -p 8080:8080 myapp:latest
+FROM golang:latest AS builder
+RUN apt-get update
+ENV GO111MODULE=on \
+    CGO_ENABLED=0 \
+    GOOS=linux \
+    GOARCH=amd64
+WORKDIR /go/src/app
+COPY go.mod .
+RUN go mod download
+# cache step
+COPY . .
+RUN go install
+
+FROM scratch
+COPY --from=builder /go/bin/myapp .
+ENTRYPOINT ["./myapp"]