Add GET /user/:userId/allowance/:allowanceId (#50)

Reviewed-on: #50

backend/db.go

@@ -86,6 +86,17 @@ func (db *Db) GetUserAllowances(userId int) ([]Allowance, error) {
 	return allowances, nil
 }
 
+func (db *Db) GetUserAllowanceById(userId int, allowanceId int) (*Allowance, error) {
+	allowance := &Allowance{}
+	err := db.db.Query("select id, name, target, progress, weight from allowances where user_id = ? and id = ?").
+		Bind(userId, allowanceId).
+		ScanSingle(&allowance.ID, &allowance.Name, &allowance.Target, &allowance.Progress, &allowance.Weight)
+	if err != nil {
+		return nil, err
+	}
+	return allowance, nil
+}
+
 func (db *Db) CreateAllowance(userId int, allowance *CreateAllowanceRequest) (int, error) {
 	// Check if user exists before attempting to create an allowance
 	exists, err := db.UserExists(userId)