Add Gin framework and create REST API endpoints

Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:1.21-alpine AS builder
+FROM --platform=$BUILDPLATFORM golang:1.21-alpine AS builder
 
 # Install git and ca-certificates
 RUN apk --no-cache add git ca-certificates
@@ -15,8 +15,13 @@ RUN go mod download
 # Copy source code
 COPY . .
 
-# Build the application
-RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o hello-api main.go
+# Build the application for target platform
+ARG TARGETPLATFORM
+ARG BUILDPLATFORM
+ARG TARGETOS
+ARG TARGETARCH
+
+RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -a -installsuffix cgo -o hello-api main.go
 
 # Final stage
 FROM alpine:latest