[golang] Bootstrap contracting and refactor the agent code

golang/pkg/database/agents.go

@@ -0,0 +1,19 @@
+package database
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"git.adyxax.org/adyxax/spacetraders/golang/pkg/model"
+)
+
+func (db *DB) SaveAgent(agent *model.Agent) error {
+	data, err := json.Marshal(agent)
+	if err != nil {
+		return fmt.Errorf("failed to marshal agent: %w", err)
+	}
+	if _, err := db.Exec(`INSERT INTO agents SET data = (json(?));`, data); err != nil {
+		return fmt.Errorf("failed to insert agent data: %w", err)
+	}
+	return nil
+}