Add ExchangeRate entity to database

db/db.go

@@ -71,6 +71,7 @@ func Connect() *gorm.DB {
 	gormDB.AutoMigrate(&Expense{})
 	gormDB.AutoMigrate(&Metric{})
 	gormDB.AutoMigrate(&Currency{})
+	gormDB.AutoMigrate(&ExchangeRate{})
 	return newUDB
 }
 

db/exchange_rate.go

@@ -0,0 +1,14 @@
+package db
+
+import "gorm.io/gorm"
+
+type ExchangeRate struct {
+	gorm.Model
+	FromCurrID uint
+	FromCurr   *Currency
+	From       uint64
+	ToCurrID   uint
+	ToCurr     *Currency
+	To         uint64
+	Rate       uint64
+}