Ability to dockerize a Beego application

This introduces a new command "dockerize" which will generate
a Dockerfile to allow a Beego Web Application to run inside Docker.

bee.go

@@ -126,6 +126,7 @@ var availableCommands = []*Command{
 	//cmdRundocs,
 	cmdMigrate,
 	cmdFix,
+	cmdDockerize,
 }
 
 var logger = GetBeeLogger(os.Stdout)