```ruby
#!/usr/bin/env ruby

require "yaml"

require "json"
require "net/http"

whitelisted_domains = %w(poczta.onet.pl fastmail.fm hushmail.com naver.com qq.com)

existing_domains = File.readlines("vendor/disposable_domains.txt")

url = "https://raw.githubusercontent.com/FGRibreau/mailchecker/master/list.json"
resp = Net::HTTP.get_response(URI.parse(url))

remote_domains = JSON.parse(resp.body).flatten - whitelisted_domains

result_domains = (existing_domains + remote_domains).map { |domain| domain.strip.downcase }.uniq.sort

File.open("vendor/disposable_domains.txt", "w") { |f| f.write result_domains.join("\n") }
```

Whitelist the University of Singapore (nus.edu.sg) the the disposable email fetcher
user
```ruby
#!/usr/bin/env ruby

require "yaml"

require "json"
require "net/http"

whitelisted_domains = %w(poczta.onet.pl fastmail.fm hushmail.com naver.com qq.com nus.edu.sg)

existing_domains = File.readlines("vendor/disposable_domains.txt")

url = "https://raw.githubusercontent.com/FGRibreau/mailchecker/master/list.json"
resp = Net::HTTP.get_response(URI.parse(url))

remote_domains = JSON.parse(resp.body).flatten - whitelisted_domains

result_domains = (existing_domains + remote_domains).map { |domain| domain.strip.downcase }.uniq.sort

File.open("vendor/disposable_domains.txt", "w") { |f| f.write result_domains.join("\n") }
```
assistant