Test in 32bit

Use i386/golang:alpine image for testing 32bit system, detail in Dockerfile.32bit

• build image

  docker build -t cvt-test -f Dockerfile.32bit .
  

• run container

  docker run -it --name cvt-test -v "$PWD":/usr/src/myapp -w /usr/src/myapp cvt-test bash
  

• run test

  go test ./...