Multi-currency support (#425)

* Initial foundational pass at multi-currency

* Default format currency

* More work on currency and exchanging

* Re-build currencies on change

* Currency import/setup

* Background job overhaul + cheaper OXR plan support

* Lint fixes

* Test fixes

* Multi-currency setup instructions

* Allow decimals in the balance field

* Spacing fix for form

---------

Signed-off-by: Josh Pigford <josh@joshpigford.com>

test/fixtures/accounts.yml

@@ -1,14 +1,14 @@
 dylan_checking:
   family: dylan_family
   name: Bob's Checking
-  balance_cents: 1200
+  original_balance: 1200
 
 dylan_roth:
   family: dylan_family
   name: Bob's Roth IRA
-  balance_cents: 1200
+  original_balance: 1200
 
 richards_savings:
   family: richards_family
   name: Keef's HYSA
-  balance_cents: 1500
+  original_balance: 1500

test/fixtures/currencies.yml

@@ -0,0 +1,9 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+# one:
+#   name: MyString
+#   iso_code: MyString
+
+# two:
+#   name: MyString
+#   iso_code: MyString

test/fixtures/exchange_rates.yml

@@ -0,0 +1,13 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  base_currency: one
+  converted_currency: one
+  rate: 9.99
+  date: 2024-02-09
+
+two:
+  base_currency: two
+  converted_currency: two
+  rate: 9.99
+  date: 2024-02-09