Compose: Yaml file syntax error

[elpirata15]

docker version

Client:
 Version:      1.8.3
 API version:  1.20
 Go version:   go1.5.1
 Git commit:   f4bf5c7
 Built:        
 OS/Arch:      linux/amd64

Server:
 Version:      1.8.3
 API version:  1.20
 Go version:   go1.5.1
 Git commit:   f4bf5c7
 Built:        
 OS/Arch:      linux/amd64

docker-compose version

docker-compose version: 1.5.0
docker-py version: 1.5.0
CPython version: 3.4.3+
OpenSSL version: OpenSSL 1.0.2d 9 Jul 2015

uname -a
Linux debian01 4.2.0-1-amd64 #1 SMP Debian 4.2.5-1 (2015-10-27) x86_64 GNU/Linux

I'm trying to setup basic wordpress + mysql container but I got an error when I try to setup the enviroment with MYSQL_ROOT_PASSWORD value starting with special character '*'

docker-compose.yml

wordpress:
  image: wordpress
  links:
    - db:mysql
  ports:
    - 8080:80

db:
  image: mysql
  environment:
    MYSQL_ROOT_PASSWORD: **$$.example

docker-compose up (Error)

ERROR: yaml.scanner.ScannerError: while scanning an alias
  in "./docker-compose.yml", line 11, column 26
expected alphabetic or numeric character, but found '*'
  in "./docker-compose.yml", line 11, column 27

Regards,

[dnephin]

You need to quote strings with special characters "**$$.example"