Add inbox_swaps endpoint with balance percentage field (#49)

sql_extensions/migrations/00006_user_rank.sql

@@ -0,0 +1,41 @@
+CREATE TABLE inbox_user_balance (
+    user_address TEXT NOT NULL PRIMARY KEY,
+    balance_as_fraction_of_circulating_supply NUMERIC
+);
+
+CREATE OR REPLACE FUNCTION UPDATE_USER_BALANCE()
+RETURNS TRIGGER AS $$
+BEGIN
+    INSERT INTO inbox_user_balance
+    SELECT
+        NEW.data ->> 'user',
+        (NEW.data ->> 'balance_as_fraction_of_circulating_supply_q64')::NUMERIC / POW(2::NUMERIC, 64::NUMERIC)
+    ON CONFLICT (user_address) DO UPDATE SET
+        balance_as_fraction_of_circulating_supply = (NEW.data ->> 'balance_as_fraction_of_circulating_supply_q64')::NUMERIC / POW(2::NUMERIC, 64::NUMERIC);
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER update_user_balance
+AFTER INSERT ON inbox_events
+FOR EACH ROW
+WHEN (new.event_name = 'emojicoin_dot_fun::Chat')
+EXECUTE PROCEDURE UPDATE_USER_BALANCE();
+
+CREATE VIEW inbox_swaps AS
+SELECT
+    swaps.sequence_number,
+    swaps.creation_number,
+    swaps.account_address,
+    swaps.transaction_version,
+    swaps.transaction_block_height,
+    swaps."type",
+    swaps."data",
+    swaps.inserted_at,
+    swaps.event_index,
+    swaps.indexed_type,
+    swaps.event_name,
+    inbox_user_balance.balance_as_fraction_of_circulating_supply
+FROM inbox_events AS swaps
+LEFT JOIN inbox_user_balance ON swaps.data ->> 'swapper' = inbox_user_balance.user_address
+WHERE swaps.event_name = 'emojicoin_dot_fun::Swap';