Create macro and use it in balance transactions

macros/generate_stripe_sources_unioned_select.sql

@@ -0,0 +1,15 @@
+/*
+This macro runs for every country code and:
+    - Reads from the right source (stripe_<country-code>)
+    - Adds a column identifying the source account with a string like "stripe_<country>_account"
+*/
+{% macro generate_stripe_sources_unioned_select(source_table) -%}
+    {% set countries = ["us", "uk"] %}
+    {% for country in countries %}
+        select *, 'stripe_{{ country }}_account' as stripe_source_account
+        from {{ source("stripe_" ~ country, source_table) }}
+        {% if not loop.last -%}
+            union all
+        {%- endif %}
+    {% endfor %}
+{%- endmacro %}