Add option values to field that already has data I created a content type with a field "Category".

In that field I added two values:
- Books
- Movies

I inserted data in this content type and I have a view showing the content per category.
Now i need to add a new value "Series" but it shows this message:

There is data for this field in the database. The field settings can no longer be changed.

What can I do?

Thank you in advance!
You should use taxonomy to create a vocabulary named Category and add terms to it. Then add a taxonomy term reference field to your content type.