title: Categorizing Hastags based on similarities
body: <p>I have different documents with a list of hashtags in each. I would like to group them under the most relevant hashtag (which would be present in the document itself). 
  Egs: If there are #Eco, # Ecofriendly # GoingGreen - I would like to group all these under the most relevant and representative Hashtag (say #Eco). How should I be approaching this and what techniques and algorithms should I be looking at?</p>