rectangles: add topics
rectangles: add topics

smalley/python,exercism/xpython,jmluy/xpython,N-Parsons/exercism-python,behrtam/xpython,behrtam/xpython,N-Parsons/exercism-python,smalley/python,exercism/python,pheanex/xpython,mweb/python,jmluy/xpython,exercism/xpython,exercism/python,pheanex/xpython,mweb/python