Taraweeh is a Bid'ah created in the year 14 after Hijra by Umar ibn Khttab. Umar himself called it Bid'ah ( Saheeh Bukhari; Hadeeth number1871 and Saheeh Muslim ; Hadeeth number 1219 , and Musnad Ahmad ibn Hanbal ; Hadeeth number 22944, and a Sunan Abi Dawood; 1143, and al-Mowatta'bby Malik ibn Ana's; 243, and Sunan al-Tirmithi ; 403, Sunan al-Kubba by al-Bayhaqi ; V.7, P. 62 and Saheeh ibn Hibban , V.6, P. 186 and many other Sunni books of Hadeeth).
imam Ali (AS) was always against every Bid'ah. He had clearly refused this practice and condemned it. When he had the government in his hand, he prevented people from Taraweeh and told them that no congregational prayer in Islam but the obligatory prayers but many of them said: It is Sunnah of Umar and we won't leave a Sunnah of Umar.( Al-Kafi 8:58).