Multiple types of Income

[TheAxelander]

Design a way of having multiple types of Income Buckets which can be then also used for specific reports on Reports Page.

Would be also a question how to handle/distinguish pre-defined Income Bucket compared to user-defined Income Buckets.

[TheAxelander]

Discussed in #167

[andyvandesand]

My suggestion would be to handle the income bucket category as required in the app, but allow multiple buckets being created inside same as for other buckets.