Added 'boxhome' argument to toolbox create command

Relates to issues containers#348, containers#467
Added optional boxhome argument to create command.
Boxhome is concatenated with homedir in order to be under host's home dir.
Homedir is still mounted. No worries.
Being under host's home enables easy file sharing, and prevents privilage issues.
When boxhome argument is not given, system works as before (uses user's home dir)

src/cmd/create.go

@@ -46,6 +46,7 @@ var (
 		distro    string
 		image     string
 		release   string
+		boxhome   string
 	}
 
 	createToolboxShMounts = []struct {
@@ -90,6 +91,12 @@ func init() {
 		"",
 		"Create a toolbox container for a different operating system release than the host")
 
+	flags.StringVarP(&createFlags.boxhome,
+		"boxhome",
+		"b",
+		"",
+		"Create a toolbox container with a different home path than the host.")
+
 	createCmd.SetHelpFunc(createHelp)
 	rootCmd.AddCommand(createCmd)
 }
@@ -381,6 +388,7 @@ func createContainer(container, image, release string, showCommandToEnter bool)
 		"init-container",
 		"--gid", currentUser.Gid,
 		"--home", currentUser.HomeDir,
+		"--boxhome", createFlags.boxhome,
 		"--shell", userShell,
 		"--uid", currentUser.Uid,
 		"--user", currentUser.Username,

src/cmd/initContainer.go

@@ -38,6 +38,7 @@ var (
 	initContainerFlags struct {
 		gid         int
 		home        string
+		boxhome     string
 		homeLink    bool
 		mediaLink   bool
 		mntLink     bool
@@ -87,6 +88,12 @@ func init() {
 		"Create a user inside the toolbox container whose login directory is HOME")
 	initContainerCmd.MarkFlagRequired("home")
 
+	fmt.Println(initContainerFlags.boxhome)
+	flags.StringVar(&initContainerFlags.boxhome,
+		"boxhome",
+		"",
+		"Create a user inside the toolbox container whose login directory is not HOME.")
+
 	flags.BoolVar(&initContainerFlags.homeLink,
 		"home-link",
 		false,
@@ -228,7 +235,7 @@ func initContainer(cmd *cobra.Command, args []string) error {
 	if _, err := user.Lookup(initContainerFlags.user); err != nil {
 		if err := configureUsers(initContainerFlags.uid,
 			initContainerFlags.user,
-			initContainerFlags.home,
+			initContainerFlags.home+"/"+initContainerFlags.boxhome,
 			initContainerFlags.shell,
 			initContainerFlags.homeLink,
 			false); err != nil {
@@ -237,7 +244,7 @@ func initContainer(cmd *cobra.Command, args []string) error {
 	} else {
 		if err := configureUsers(initContainerFlags.uid,
 			initContainerFlags.user,
-			initContainerFlags.home,
+			initContainerFlags.home+"/"+initContainerFlags.boxhome,
 			initContainerFlags.shell,
 			initContainerFlags.homeLink,
 			true); err != nil {