Add update command.

Signed-off-by: Odyssey <hi@odyssey346.dev>

.gitignore

@@ -23,8 +23,5 @@ go.work
 
 tmp/
 
-# Gothub binary.
-gothub
-
 # Fiber compressed files
 *.fiber.gz

cmd/gothub/update.go

@@ -0,0 +1,62 @@
+package gothub
+
+import (
+	"bytes"
+
+	"github.com/spf13/cobra"
+
+	"os"
+	"os/exec"
+	"runtime"
+)
+
+var updateCmd = &cobra.Command{
+	Use:   "update",
+	Short: "Update GotHub.",
+	Long:  `This command checks for updates and re-builds GotHub. Does not work on Docker`,
+	Run: func(cmd *cobra.Command, args []string) {
+		update()
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(updateCmd)
+}
+
+func update() {
+	if os.Getenv("DOCKER") == "true" {
+		println("The GotHub update command does not work on Docker. Just re-create the container with a new image.")
+		os.Exit(1)
+	}
+	gitPull := exec.Command("git", "pull")
+	var out bytes.Buffer
+	gitPull.Stdout = &out
+	err := gitPull.Run()
+	if out.String() == "Already up to date.\r" {
+		println("GotHub is already up to date.")
+		os.Exit(0)
+	}
+	if err != nil {
+		println("Couldn't run Git pull. Are you using Git?", err)
+		os.Exit(1)
+	}
+	if runtime.GOOS == "windows" {
+		err := exec.Command("go", "build", "-o", "gothub.exe").Run()
+		if err != nil {
+			println("Couldn't build GotHub. ", err)
+			os.Exit(1)
+		} else {
+			println("GotHub updated successfully.")
+			os.Exit(0)
+		}
+	} else {
+		err := exec.Command("go", "build").Run()
+		if err != nil {
+			println("Couldn't build GotHub. ", err)
+			os.Exit(1)
+		} else {
+			println("GotHub updated successfully.")
+			os.Exit(0)
+		}
+	}
+}