Bug: Income transactions summed under Expenses in summary

[jakubkottnauer]

The bug
Creating a new Income transaction results in "Expenses" section in the summary increasing. Likewise when an Expense transaction is created, "Income" summary increases.

To Reproduce
Steps to reproduce the behavior:

1. Create a new Income transaction (for example in a Checking account)
2. Go to /transactions
3. Observe that the Expenses section at the top of the page has increased by the transaction amount

Expected behavior
Income transactions should be summed under Incomes (similarly for expenses).

Screenshots
Income of $100 in a checking account shown as a $100 total expense.