Change `add_team_member` to `add_team_membership` method
Change `add_team_member` to `add_team_membership` method

add_team_member method is deprecated

SEE ALSO:
https://developer.github.com/changes/2014-08-05-team-memberships-api/

assemblymade/coderwall,alouanemed/coderwall,wiserfirst/coderwall,assemblymade/coderwall,pombredanne/coderwall,coderwall/coderwall,trinitronx/coderwall,ronaldotijucas/coderwall,trinitronx/coderwall,pushkar-mishra/coderwall,DylanKojiCheslin/coderwall,sekouzed/coderwall,coderwall/coderwall,pombredanne/coderwall,wiserfirst/coderwall,assemblymade/coderwall,assemblymade/coderwall,wiserfirst/coderwall,ronaldotijucas/coderwall,agileknight/coderwall,pushkar-mishra/coderwall,DylanKojiCheslin/coderwall,pombredanne/coderwall,alouanemed/coderwall,ronaldotijucas/coderwall,alouanemed/coderwall,agileknight/coderwall,DylanKojiCheslin/coderwall,pushkar-mishra/coderwall,coderwall/coderwall,sekouzed/coderwall,seuros/coderwall,santoshdeshpande/coderwall,wiserfirst/coderwall,sekouzed/coderwall,pushkar-mishra/coderwall,agileknight/coderwall,alouanemed/coderwall,trinitronx/coderwall,ronaldotijucas/coderwall,seuros/coderwall,santoshdeshpande/coderwall,coderwall/coderwall,seuros/coderwall,santoshdeshpande/coderwall,pombredanne/coderwall,trinitronx/coderwall,seuros/coderwall,agileknight/coderwall,sekouzed/coderwall