feat: add contact model

internal/models/contact.go

@@ -0,0 +1,8 @@
+package models
+
+type Contact struct {
+	ID      int    `json:"id" db:"id"`
+	Name    string `json:"name" db:"name"`
+	Company string `json:"company" db:"company"`
+	Phone   string `json:"phone" db:"phone"`
+}