Please tell me more about Champaran movement & Mahatma Gandhi's role in it

Champaran, a district in state of Bihar, was the first of the places where Mahatma Gandhi experimented with his theory of satyagrah in India. Tens of thousands of landless serfs, indentured laborers and poor farmers were forced to grow indigo and other cash crops instead of the food crops necessary for their survival. These goods were bought from them at a very low price. The farmers were given paltry compensation, leaving them mired in extreme poverty. The British levied an oppressive tax which they insisted on increasing in rate. Without food and without money, the situation was growing progressively unlivable and the peasants in Champaran revolted against indigo plant cultivation in 1914 (at Pipra) and 1916(Turkaulia). In this scenario, Mahatma Gandhi took over the leadership and it turned out to be a success.