Add confirmation struct

config/postgres.sql

@@ -13,3 +13,8 @@ CREATE UNIQUE INDEX product_trade_id_index ON trades (
 	trade_id);
 
 CREATE INDEX timestamp_index ON trades (timestamp);
+
+CREATE TABLE confirmations (
+	id SERIAL PRIMARY KEY,
+	product CHAR(7) NOT NULL,
+	last_trade_id INTEGER NOT NULL DEFAULT 0);

confirmation.go

@@ -0,0 +1,13 @@
+package tacitus
+
+type Confirmation struct {
+	Id          int    `json:"id"`
+	Product     string `json:"product"`
+	LastTradeId int    `json:"last_trade_id"`
+}
+
+type ConfirmationService interface {
+	Confirmation(product string) (*Confirmation, error)
+	CreateConfirmation(c *Confirmation) error
+	UpdateConfirmation(c *Confirmation) error
+}