By Ellen Chang With crude oil prices rising towards $100 a barrel on Ukraine tensions and tight supplies, industry watchers see fuel price rises continuing for months. Crude oil prices reached $90 a barrel on Thursday for the first time since 2014 on greater uncertainty over Russian saber rattling at Ukraine and tight supplies elsewhere. Oil reaching the $90 mark is “certainly another psychological barrier passed,” said Patrick De Haan, head of petroleum analysis at GasBuddy, a Boston-based provider of retail fuel pricing information and data. The national average price for gasoline should con…