def invite_friend(opts)
      unless opts[:email] || opts[:user_id]
        raise InvalidArgumentError.new "invite_friend hash argument must include :email or :user_id"
      end
      translated_options = {}
      translated_options[:invitedUserEmail] = opts[:email] if opts[:email]
      translated_options[:invitedUserId] = opts[:user_id] if opts[:user_id]
      post("/user/#{@user_id}/friends/invitations.json", translated_options)
    end
def invite_friend(opts)
      unless opts[:email] || opts[:user_id]
        raise InvalidArgumentError.new "invite_friend hash argument must include :email or :user_id"
      end
      translated_options = {}
      translated_options[:invitedUserEmail] = opts[:email] if opts[:email]
      translated_options[:invitedUserId] = opts[:user_id] if opts[:user_id]
      post("/user/#{@user_id}/friends/invitations.json", translated_options)
    end
==========================================
       Invitation Management Methods
 ==========================================
 Create an invite for a user to connect with the current user as a friend

 In order to invite a user, either an :email or a valid :userId
 must be supplied in the +opts+ param hash.

 @param [Hash] opts The invite data
 @option opts [String] :email Email address of user to invite
 @option opts [String] :userId User ID of the user to invite

 @return [Hash]