feat(cli): add version and add homebrew tap

Author: zcong1993

.goreleaser.yml

@@ -1,7 +1,7 @@
 builds:
   - main: cmd/main.go
     binary: leetcode-tool
-    ldflags: -s -w -X main.GitCommit={{.Commit}} -X main.Date={{.Date}}
+    ldflags: -s -w -X main.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{ .CommitDate }} -X main.builtBy=goreleaser
     goos:
       - windows
       - darwin
@@ -16,3 +16,12 @@ changelog:
       - '^refactor'
       - '^tweak'
       - '^test'
+brews:
+  - github:
+      owner: zcong1993
+      name: homebrew-tap
+    folder: Formula
+    homepage: https://github.com/zcong1993/leetcode-tool
+    description: 一个让你更方便刷题的工具
+    test: |
+      system "#{bin}/leetcode-tool -v"

cmd/main.go

@@ -13,6 +13,13 @@ import (
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
+var (
+	version = "master"
+	commit  = ""
+	date    = ""
+	builtBy = ""
+)
+
 var (
 	app = kingpin.New("algo", "A command-line tool for algo-go repo.")
 
@@ -40,6 +47,10 @@ func showMeta(number string) {
 }
 
 func main() {
+	app.Version(buildVersion(version, commit, date, builtBy))
+	app.VersionFlag.Short('v')
+	app.HelpFlag.Short('h')
+
 	switch kingpin.MustParse(app.Parse(os.Args[1:])) {
 	case updateCmd.FullCommand():
 		update.Run()
@@ -51,3 +62,17 @@ func main() {
 		tags.Run()
 	}
 }
+
+func buildVersion(version, commit, date, builtBy string) string {
+	var result = version
+	if commit != "" {
+		result = fmt.Sprintf("%s\ncommit: %s", result, commit)
+	}
+	if date != "" {
+		result = fmt.Sprintf("%s\nbuilt at: %s", result, date)
+	}
+	if builtBy != "" {
+		result = fmt.Sprintf("%s\nbuilt by: %s", result, builtBy)
+	}
+	return result
+}