fix: Always exit 0 by default

lib/vimpk/cli.rb

@@ -19,6 +19,7 @@ def initialize(argv)
     def call
       if @command
         send(@command, *@argv)
+        exit 0
       else
         puts @parser.parser
       end
@@ -37,6 +38,8 @@ def determine_command
       case name
       when "i", "install"
         :install_command
+      when "l", "list"
+        :list_command
       when "mv", "move"
         :move_command
       when "u", "update"
@@ -49,6 +52,12 @@ def determine_command
       end
     end
 
+    def list_command
+      command = List.new(@options)
+      list = command.call
+      puts list.sort_by(&:downcase)
+    end
+
     def install_command(package = nil)
       time = Time.now
       install = Install.new(package, @options)