chore: add a command to build a binary for Linux.

Usage:

$ make build-linux
$ ./my-country-linux

Author: php-coder

.gitignore

@@ -1 +1,2 @@
 my-country
+my-country-linux

Makefile

@@ -1,10 +1,13 @@
-.PHONY: build fmt clean
+.PHONY: build build-linux fmt clean
 
 build:
 	go build -o my-country .
 
+build-linux:
+	GOOS=linux GOARH=amd64 go build -o my-country-linux .
+
 fmt:
 	gofmt -s -d -w .
 
 clean:
-	rm my-country
+	rm my-country my-country-linux