# for username: 
# Username may only contain alphanumeric characters or single hyphens, and cannot begin or end with a hyphen
# for repo url:
# any valid alphanumeric including underscores

import re
def validate_repo_url(value):
    reg = re.compile('^([a-zA-Z\d]{1}[-a-zA-Z\d]+)(/){1}([\-\w]+)$')