init: added the base files by ai and debugged by hand

it's great but currently it has a basic error which is go nil pointer dereference

WIP

Dockerfile

@@ -0,0 +1,38 @@
+# Production-hardened Dockerfile for auth-gate
+#
+# We use a multi-stage build to keep the final image small.
+# The build stage compiles the binary, and the runtime stage copies
+# only the binary and the required configuration.
+
+FROM golang:1.21-alpine AS builder
+WORKDIR /app
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+RUN CGO_ENABLED=0 GOOS=linux go build -o auth-gate .
+
+# Runtime stage
+FROM alpine:3.19
+WORKDIR /app
+
+# Create a non-root user (security best practice).
+RUN addgroup -S auth-gate && adduser -S auth-gate -G auth-gate
+
+# Copy the binary from the builder stage.
+COPY --from=builder /app/auth-gate .
+
+# Create directories for config and data.
+RUN mkdir -p /config /data
+
+# Set ownership so the non-root user can write to /data but not /config.
+RUN chown -R auth-gate:auth-gate /data && chown auth-gate:auth-gate /config
+
+# Switch to the non-root user.
+USER auth-gate
+
+# Expose the HTTP port.
+EXPOSE 8080
+
+# Start the service.
+ENTRYPOINT ["/app/auth-gate"]
+CMD []