[hw-4] add postgres db

loms/internal/infra/tools/safecast.go

@@ -0,0 +1,19 @@
+package tools
+
+import (
+	"fmt"
+	"math"
+)
+
+func SafeCastInt64ToUInt32(num int64) (uint32, error) {
+	if num < 0 {
+		return 0, fmt.Errorf("tried casting signed negative number to unsigned number")
+	}
+
+	if num > math.MaxUint32 {
+		return 0, fmt.Errorf("tried casting larger number than uint32 can store")
+	}
+
+	// the bounds are checked, and cast should be safe.
+	return uint32(num), nil // #nosec G115
+}