Release 0.2.0

- new language: go
- new shops: cybertek.fr, mediamarkt.ch
- deprecated shops: alternate.be, minershop.eu
- improved database transaction management
- better web parsing library (ferret, requires headless chrome browser)
- include or exclude products by applying regex on their names
- check for PID file to avoid running the bot twice
- hastags are now configurable

Signed-off-by: Julien Riou <julien@riou.xyz>

models.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"gorm.io/gorm"
+)
+
+// Product is self-explainatory
+type Product struct {
+	gorm.Model
+	Name          string  `gorm:"not null" json:"name"`
+	URL           string  `gorm:"unique" json:"url"`
+	Price         float64 `gorm:"not null" json:"price"`
+	PriceCurrency string  `gorm:"not null" json:"price_currency"`
+	Available     bool    `gorm:"not null;default:false" json:"available"`
+	ShopID        uint
+	Shop          Shop
+}
+
+// Equal compares a database product to another product
+func (p *Product) Equal(other *Product) bool {
+	return p.URL == other.URL && p.Available == other.Available
+}
+
+// IsValid returns true when a Product has all required values
+func (p *Product) IsValid() bool {
+	return p.Name != "" && p.URL != "" && p.Price != 0 && p.PriceCurrency != ""
+}
+
+// Merge one product with another
+func (p *Product) Merge(o *Product) {
+	p.Price = o.Price
+	p.PriceCurrency = o.PriceCurrency
+	p.Available = o.Available
+}
+
+// ToMerge detects if a product needs to be merged with another one
+func (p *Product) ToMerge(o *Product) bool {
+	return p.Price != o.Price || p.PriceCurrency != o.PriceCurrency || p.Available != o.Available
+}
+
+// Shop represents a retailer website
+type Shop struct {
+	ID   uint   `gorm:"primaryKey"`
+	Name string `gorm:"unique"`
+}