Scope config option to isolate translations

[vipera]

In my usage of this gem, I ran into a situation where I'd like two very related applications that are organizationally distinct but part of the same domain (e.g. public web application and its admin/management application) to connect to the same database.

However, I'd like them not to share translation data, and found that difficult to do without overriding methods in I18n::Backend::ActiveRecord. So instead, I added this feature to my fork, and wanted to see what you think about it and whether you'd be interested in having it in the main codebase.

Essentially I added a scope field to the migration and if the configuration option is set, then all reads/writes will be limited to only those records with that particular scope identifier. I wanted to maintain compatibility with existing tables that don't have a scope, or even newly created tables where someone wants to remove the scope field from the migration if they won't be using it.

I've added two tests showing how I think the behaviour should work and a readme paragraph. Thanks taking the time to look this over ☺️

[timfjord]

It is looking good 👍🏻, there are some failed tests though

[vipera]

Thanks for your input, Tim!

I glanced over the pipeline logs and it looks like tests are failing on the master branch too for the same reasons. As usual, test pipelines stop being reliable after a while...

I can look into the details to try and fix it, but I don't think it's related to the change I made.

[timfjord]

Hmm, indeed, master is broken.
It would be great to fix the tests(if you have bandwidth of course) otherwise, I will try to fix master so we can go ahead with this is PR