In double-entry accounting, all transactions should have a double-entry. If the transaction is a credit, then the double-entry is a debit and vice versa. Also, the transaction amount is positive or negative depending on if the account the transaction is in is a debit account or a credit account. Example: If you create a salary transaction in the income account, that should be a credit which is a positive number. If the double-entry account is the checking account, that is a debit account so it's entry should also be a positive number.
Merge pull request #149 from jesseshieh/js/double-entry-debit-credit-fix

Double-entry accounting positive and negative debits and credits