Adds a week to a date. The value must be of the form {{Y,M,D},{H,I,S}}.

For example:

{{ value|add_week }}

When the value is {{2008,12,10},{15,30,0}}, the output is {{2008,12,17},{15,30,0}}.

The filter has an optional argument which defines the number of weeks to add:

{{ value|add_week:4 }}

When the value is {{2008,12,10},{15,30,0}}, the output is {{2009,1,7},{15,30,0}}.