add migration script to add unique index for kline tables

migrations/mysql/20220520140707_kline_unique_idx.sql

@@ -0,0 +1,68 @@
+-- +up
+
+-- +begin
+TRUNCATE TABLE `binance_klines`;
+-- +end
+
+-- +begin
+TRUNCATE TABLE `max_klines`;
+-- +end
+
+-- +begin
+TRUNCATE TABLE `ftx_klines`;
+-- +end
+
+-- +begin
+TRUNCATE TABLE `kucoin_klines`;
+-- +end
+
+-- +begin
+TRUNCATE TABLE `okex_klines`;
+-- +end
+
+-- +begin
+CREATE UNIQUE INDEX idx_kline_binance_unique
+    ON binance_klines (`symbol`, `interval`, `start_time`);
+-- +end
+
+-- +begin
+CREATE UNIQUE INDEX idx_kline_max_unique
+    ON max_klines (`symbol`, `interval`, `start_time`);
+-- +end
+
+-- +begin
+CREATE UNIQUE INDEX `idx_kline_ftx_unique`
+    ON ftx_klines (`symbol`, `interval`, `start_time`);
+-- +end
+
+-- +begin
+CREATE UNIQUE INDEX `idx_kline_kucoin_unique`
+    ON kucoin_klines (`symbol`, `interval`, `start_time`);
+-- +end
+
+-- +begin
+CREATE UNIQUE INDEX `idx_kline_okex_unique`
+    ON okex_klines (`symbol`, `interval`, `start_time`);
+-- +end
+
+-- +down
+
+-- +begin
+DROP INDEX `idx_kline_ftx_unique` ON `ftx_klines`;
+-- +end
+
+-- +begin
+DROP INDEX `idx_kline_max_unique` ON `max_klines`;
+-- +end
+
+-- +begin
+DROP INDEX `idx_kline_binance_unique` ON `binance_klines`;
+-- +end
+
+-- +begin
+DROP INDEX `idx_kline_kucoin_unique` ON `kucoin_klines`;
+-- +end
+
+-- +begin
+DROP INDEX `idx_kline_okex_unique` ON `okex_klines`;
+-- +end

migrations/sqlite3/20220520140707_kline_unique_idx.sql

@@ -0,0 +1,10 @@
+-- +up
+-- +begin
+SELECT 'up SQL query';
+-- +end
+
+-- +down
+
+-- +begin
+SELECT 'down SQL query';
+-- +end