make dockerfile multiplatofrm

Dockerfile

@@ -1,10 +1,21 @@
-FROM golang:1.25.6-alpine AS builder
+FROM --platform=$BUILDPLATFORM golang:1.25.6-alpine AS builder
 WORKDIR /app
+
+RUN apk add --no-cache git ca-certificates tzdata
+
 COPY go.mod go.sum ./
 RUN go mod download
+
 COPY . .
-RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo \
-    -ldflags="-w -s" -trimpath -o pm ./cmd/survey/
+
+ARG TARGETOS
+ARG TARGETARCH
+
+RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build \
+    -a -installsuffix cgo \
+    -ldflags="-w -s" \
+    -trimpath \
+    -o pm ./cmd/survey/
 
 FROM gcr.io/distroless/static-debian13
 WORKDIR /data