Finish expense tracker challenge

Signed-off-by: Michael Tang <michael.h.tang@gmail.com>

objects-references.js

@@ -0,0 +1,44 @@
+let myAccount = {
+    name: 'Andrew',
+    expenses: 0,
+    income: 0
+}
+
+let addExpense = function (account, amount) {
+    account.expenses = account.expenses + amount
+    console.log(`${amount} in expensese logged for account ${account.name}.`)
+}
+
+// addIncome
+let addIncome = function (account, amount) {
+    account.income = account.income + amount
+    console.log(`${amount} in income logged for account ${account.name}.`)
+}
+
+// resetAccount 
+let resetAccount = function(account) {
+    account.expenses = 0
+    account.income = 0
+    console.log(`Account for ${account.name} has been reset.`)
+}
+
+// getAccountSummary
+// Account for Andrew has $900. $1000 in income. $100 in expenses.
+let getAccountSummary = function(account) {
+    console.log(`Account for ${account.name} has ${(account.income) - (account.expenses)}. ${account.income} in income. ${account.expenses} in expenses. `)
+}
+
+
+// addIncome
+// addExpense
+// getAccountSummary
+// resetAccount
+// getAccountSummary
+
+addIncome(myAccount, 1000)
+addExpense(myAccount, 50)
+addExpense(myAccount, 50)
+getAccountSummary(myAccount)
+resetAccount(myAccount)
+getAccountSummary(myAccount)
+