Add series placemark form field under series

[BrittanyBunk]

Problem:

• books are in order when published in a series

Solution:

• add a form field to assign books numbers to show where a book stands in a series

Example

• Harry Potter and the Sorcerer's Stone - given Add a setup.py #1, Chamber of Secrets - catalog/onix/onix.py attempts to use a global variable in init(), but doesn't declare it global #2, etc.