Add a recommendation to manually set the DJANGO_SQIDS_ALPHABET setting

[apoorvaeternity]

By customizing the DJANGO_SQIDS_ALPHABET string, we can prevent the issue of generating the same IDs as those generated by other projects using the default alphabet.

[julianwachholz]

Sorry for not getting back sooner, I've been thinking about this notice a bit.

Personally, I want to avoid any references to potential "security" issues as this is not a security library and must not be used as such. Mentioning that it's recommended to change the alphabet (I don't think it is, I haven't seen this mentioned anywhere around the Sqids project?) might make people think it's for better security or similar.

Because of this I'm closing this for now.

[apoorvaeternity]

@julianwachholz - No worries. I know djando-sqids is purely visual and providing a random string won't change anything in terms of security. It was just to ensure that the outputs were visually unique.
I saw this recommendation in: https://github.com/sqids/sqids-dotnet#customizations and felt it would be a nice addition here.

[julianwachholz]

Thanks for the link. This Python package does provide a small shuffle_alphabet utlity to achieve the same effect. Would you like to mention this in the README instead?

[apoorvaeternity]

@julianwachholz Sure! I saw the shuffle_alphabet utility.
The only caveat with it is that it has to be run manually to get the output, which is a tad cumbersome, so I opted for the online utility.

I guess we can mention both like this:
You may use the shuffle_alphabet function provided with django-sqids or an online tool like [this one](https://codebeautify.org/shuffle-letters) to shuffle the default string.

WDYT?

[julianwachholz]

Sorry, I do not wish to link to a third party site for this. I am interested in adding the function as a script to be invoked (manage.py or python -m)

[apoorvaeternity]

@julianwachholz Okay - let's just keep it as:
You may use the shuffle_alphabet function provided with django-sqids to shuffle the default string.

[apoorvaeternity]

@julianwachholz - Do you have the option to re-open the pull request? If not, I can create another one.

[apoorvaeternity]

@julianwachholz - I am going to add a script to generate a random string that can be used as DJANGO_SQIDS_ALPHABET. I was thinking of adding it as a management command but then the django_sqids app would have to be added to INSTALLED_APPS, which isn't a requirement at the moment.
Eitehr we can ask users to add django_sqids to INSTALLED_APPS going forwards and create a management command or we can just create a script which would return a randomised string using the default alphabet.

python -m django_sqids.generate_random_alphabet
t8WPbaXQ30R9umoTCAHBIswgUNqhlLpYdxvJGkfzrSeKD1VMcZj7O42Fi5E6yn

It is probably a one time use thing per-project anyway(unless the user is manually providing a different alphabet for each field)

WDYT?

[julianwachholz]

Agreed the python -m way is quick and clean. :)

[apoorvaeternity]

@julianwachholz - have added a small script for random alphabet generation.