Add migrations helper and refactor DB operations with environment variable support

helpers/dbHelpers.go

@@ -5,6 +5,10 @@ import (
 	"gorm.io/gorm"
 )
 
+func AddMigrations(db *gorm.DB) {
+	db.AutoMigrate(&models.Post{}, &models.MediaAttachment{}, &models.Account{})
+}
+
 func GetExistingPostIds(db *gorm.DB) []string {
 	var existingPostIds []string
 	db.Model(&models.Post{}).Pluck("id", &existingPostIds)