Is your feature request related to a problem? Please describe.

In some cases, like testing notifications or paginations or situations where a lot of data is required to successfully develop a feature, the developer would want to increase the amount of data the development DB contains.

Since increasing default seed data is going to slow down the developer experience of casual contributors (but also regular ones), we should lean on the ability to add data to a DB that's already seeded, instead of merely increase its default size.

Describe alternatives you've considered

The premise here is that the developer has to be able to essentially do two things:

• increase the amount of data (which could be everything or in an advanced capability only a type of resource, eg. articles or notifications)
• specify the ID of the user (likely themselves) to attribute things like articles to.

I'm going to list the possible solutions:

• add environment variables for the seed file (but it would still have the issue of resetting the db and hence deleting the developer's user account)
• add an additional rake task that can use parameters and/or environment variables to add things to an already seeded database
• split the seed in various files with gems like seedbank

Additional context

See #2361 for a past discussion