Adds link to arkenfox's user.js as alternative to FF containers (#127)

README.md

@@ -84,7 +84,7 @@ This section outlines the steps you can take, to be better protected from threat
 **Keep Browser Up-to-date** | Recommended | Browser vulnerabilities are constantly being [discovered](https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=browser) and patched, so it’s important to keep it up to date, to avoid a zero-day exploit. You can [see which browser version your using here](https://www.whatismybrowser.com/), or follow [this guide](https://www.whatismybrowser.com/guides/how-to-update-your-browser/) for instructions on how to update. Some browsers will auto-update to the latest stable version
 **Check for HTTPS** | Recommended | If you enter information on a non-HTTPS website, this data is transported unencrypted and can therefore be read by anyone who intercepts it. Do not enter any data on a non-HTTPS website, but also do not let the green padlock give you a false sense of security, just because a website has SSL certificate, does not mean that it is legitimate or trustworthy. <br>[HTTPS-Everywhere](https://www.eff.org/https-everywhere) (developed by the EFF) is a lightweight, open source (on [GitHub](https://github.com/EFForg/https-everywhere)) browser addon, that by enables HTTPS encryption automatically on sites that are known to support it. Is included in Brave, Tor and mobile Onion-Browser, and is available for [Chromium](https://chrome.google.com/webstore/detail/https-everywhere/gcbommkclmclpchllfjekcdonpmejbdp), [Firefox](https://addons.mozilla.org/en-US/firefox/addon/https-everywhere/) and [Opera](https://addons.opera.com/en/extensions/details/https-everywhere/)
 **Use DNS-over-HTTPS** | Recommended | Traditional DNS makes requests in plain text for everyone to see. It allows for eavesdropping and manipulation of DNS data through man-in-the-middle attacks. Whereas [DNS-over-HTTPS](https://en.wikipedia.org/wiki/DNS_over_HTTPS) performs DNS resolution via the HTTPS protocol, meaning data between you and your DNS resolver is encrypted. A popular option is [Cloudflare's 1.1.1.1](https://1.1.1.1/help), or [compare providers](https://www.privacytools.io/providers/dns)- it is simple to [enable](https://www.maketecheasier.com/enable-dns-over-https-various-browsers) in-browser. Note that DoH comes with it's [own issues](https://blog.mozilla.org/netpolicy/2020/02/25/the-facts-mozillas-dns-over-https-doh/), mostly preventing web filtering
-**Multi-Session Containers** | Recommended | Compartmentalisation is really important to keep different aspects of your browsing separate. For example, using different profiles for work, general browsing, social media, online shopping etc will reduce the number associations that data brokers can link back to you. One option is to make use of [Firefox Containers](https://support.mozilla.org/en-US/kb/containers) which is designed exactly for this purpose. Alternatively, you could use [different browsers for different tasks](https://medium.com/fast-company/incognito-mode-wont-keep-your-browsing-private-do-this-instead-dd64bc812010) (Brave, Firefox, Tor etc). For Chromium-based browsers, you can create and use [Profiles](https://www.chromium.org/developers/creating-and-using-profiles), or an extension such as [SessionBox](https://sessionbox.io), however this addon is not open source
+**Multi-Session Containers** | Recommended | Compartmentalisation is really important to keep different aspects of your browsing separate. For example, using different profiles for work, general browsing, social media, online shopping etc will reduce the number associations that data brokers can link back to you. One option is to make use of [Firefox Containers](https://support.mozilla.org/en-US/kb/containers) which is designed exactly for this purpose. As mentioned in [#127](https://github.com/Lissy93/personal-security-checklist/issues/127), it's possible to use compartmentalize websites without containers, as done in [@arkenfox's user.js](https://github.com/arkenfox/user.js). Alternatively, you could use [different browsers for different tasks](https://medium.com/fast-company/incognito-mode-wont-keep-your-browsing-private-do-this-instead-dd64bc812010) (Brave, Firefox, Tor etc). For Chromium-based browsers, you can create and use [Profiles](https://www.chromium.org/developers/creating-and-using-profiles), or an extension such as [SessionBox](https://sessionbox.io), however this addon is not open source
 **Use Incognito** | Recommended | When using someone else's machine, ensure that you're in a private/ incognito session (Use `Ctrl+Shift+N`/ `Cmd+Shift+N`). This will prevent browser history, cookies and some data being saved, but is not [fool-proof](https://www.howtogeek.com/117776/htg-explains-how-private-browsing-works-and-why-it-doesnt-offer-complete-privacy/)- you can still be tracked
 **Understand Your Browser Fingerprint** | Recommended | Browser [Fingerprinting](https://pixelprivacy.com/resources/browser-fingerprinting) is an incredibly accurate method of tracking, where a website identifies you based on your device information, including: browser and OS versions, headers, time zone, installed fonts, plugins and applications and sometimes device hardware among other data points. You can view your fingerprint at [amiunique.org](https://amiunique.org/fp)- The aim is to be as un-unique as possible
 **Manage Cookies** | Recommended | Clearing cookies regularly is one step you can take to help reduce websites from tracking you. Cookies may also store your session token, which if captured, would allow someone to access your accounts without credentials (often called [Session Hijacking](https://en.wikipedia.org/wiki/Session_hijacking)). <br>To mitigate this you should [clear cookies](https://kb.iu.edu/d/ahic) often. [Self Destructing Cookies](https://add0n.com/self-destructing-cookies.html) is a browser addon, which will kill cookies when you close the browser