tsk-8: Added docker support (#13)

Closes #8

Reviewed-on: phoenix/textsender-auth#13
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

Dockerfile

@@ -0,0 +1,52 @@
+# Multi-stage Dockerfile for Go application
+FROM golang:1.25.3 AS builder
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    openssh-client git
+
+RUN mkdir -p -m 0700 ~/.ssh && \
+    ssh-keyscan git.kundeng.us >> ~/.ssh/known_hosts
+
+# Configure Git to use SSH for GitHub
+RUN git config --global url."ssh://git@git.kundeng.us".insteadOf "https://git.kundeng.us"
+
+# Set up the Go environment for private modules
+ENV GOPRIVATE=git.kundeng.us
+
+
+# Copy go mod and sum files
+COPY go.mod go.sum ./
+
+RUN --mount=type=ssh mkdir src && \
+    go mod download
+
+# Copy source code
+COPY ./cmd ./cmd
+COPY ./internal ./internal
+COPY ./Makefile .
+COPY ./.env .
+COPY ./migrations ./migrations
+
+# Build the application
+RUN CGO_ENABLED=0 GOOS=linux make build
+
+# Runtime stage
+FROM alpine:latest AS production
+
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /root/
+
+# Copy the pre-built binary file from the previous stage
+COPY --from=builder /app/textsender-auth .
+COPY --from=builder /app/.env ./
+COPY --from=builder /app/migrations ./migrations
+
+# Expose port
+EXPOSE 9080
+
+# Command to run the executable
+CMD ["./textsender-auth"]