Support for tags

[clamprecht]

Creating this issue to start community discussion for adding support for tags. Currently categories don't allow more than one value per category per document. For example, if a doc has a category "material", with values like metal, plastic, wood, each document can only have one value for this category.

Santip mentioned on this HN thread some limitations of the current categories implementation, and the possibility of adding tags:

IndexTank categories are not designed for the tags use case, and will not work properly. It's intended for a relatively small amount of categories for which each document has a single value. The amount of different values of a category can be large but the amount of categories cannot. If you want to implement something like tags, then each tag should be a category because you'll want more than a single tag per document. We were in the process of designing a new feature to support this kind of use cases, and maybe we'll start a branch to implement it and hopefully the community will colaborate.