User-entered transactions should appear in correct month

[MitchellDill]

Accounts page is currently showing user-entered transactions for multiple months in the same month category. I should probably drop some of my prior user-entered transactions, as those are definitely also contributing to the weirdness, but I think a pass to ensure transactions are being added to and being read from a consistent place for the dashboard, budget, accounts, and trends page would be very beneficial.

I'll add replication steps when I get a moment to revisit this!

UPDATE 8/24/19
When adding a transaction to May from the dashboard, here are what the different pages read it as:

• Dashboard - May
• Trends - May
• Budget - April
• Accounts - April