Implement attribute validation

[greenstack]

When building decks, it would be nice to apply validation to certain values:

Some examples include:

• A card has an elemental type. Since there are limited types, and it would be nice to be able to define what those limitations are.
• A hero has a health attribute. It would be nice to set a regex that limits that attribute to either a number or another game-specific special symbol.

A simple implementation could be just setting a regex, but I would also like to see creating a list of valid values that could be selected from a dropdown.

A stretch goal could also be allowing attributes to use existing validation criteria (using Pokemon as an example, using the same validation to select both the card's type and weakness).

[hristoiankov]

The card attributes actually have a hidden 'type' value for features like this. I'll need to make a list of what those types could be before committing to an implementation. Current ideas: number, text, textarea, enum (what you're proposing). I do also like the regex idea too, it would be the quickest to implement.

[hristoiankov]

This feature is now implemented. When creating attributes, you can choose your attribute type to be 'option'. You can then define the options available to that attribute.

In the card editor, there is a dropdown for selecting from the defined options.