remove outdated docs and add simple version command

docs/documentation.md

@@ -2,24 +2,4 @@
 
 ## Functionality
 
-```shell
-COMMANDS:
-     check-tools, ct  Check if docker is running
-     shell            Start a subshell for a cluster
-     create, c        Create a single- or multi-node k3s cluster in docker containers
-     delete, d, del   Delete cluster
-     stop             Stop cluster
-     start            Start a stopped cluster
-     list, ls, l      List all clusters
-     get-kubeconfig   Get kubeconfig location for cluster
-     help, h          Shows a list of commands or help for one command
-
-GLOBAL OPTIONS:
-   --verbose      Enable verbose output
-   --help, -h     show help
-   --version, -v  print the version
-```
-
-## Compatibility with `k3s` functionality/options
-
 ... under construction ...

main.go

@@ -23,19 +23,6 @@ func main() {
 	app.Name = "k3d"
 	app.Usage = "Run k3s in Docker!"
 	app.Version = version.GetVersion()
-	app.Authors = []cli.Author{
-		{
-			Name:  "Thorsten Klein",
-			Email: "iwilltry42@gmail.com",
-		},
-		{
-			Name:  "Rishabh Gupta",
-			Email: "r.g.gupta@outlook.com",
-		},
-		{
-			Name: "Darren Shepherd",
-		},
-	}
 
 	// commands that you can execute
 	app.Commands = []cli.Command{
@@ -237,6 +224,14 @@ func main() {
 			},
 			Action: run.ImportImage,
 		},
+		{
+			Name:  "version",
+			Usage: "print k3d and k3s version",
+			Action: func(c *cli.Context) {
+				fmt.Println("k3d version", version.GetVersion())
+				fmt.Println("k3s version", version.GetK3sVersion())
+			},
+		},
 	}
 
 	// Global flags