The category chart probably won't work with depository accounts in production

[phoenixy1]

Pattern doesn't seem to have different handling for positive vs. negative spending amounts based on the account type, even though Plaid requires this handling. Since, in production, spending from checking and savings accounts is represented as negative (money flowing out of the account), I anticipate that this spending will not appear in the spending pie chart correctly, although I haven't tested this. Leaving this issue here as a TODO.