Vector Space Model with Nutch and Solr

Question

I'm new to both NUTCH and SOLR, and I have to build a search engine based on these two in my capstone project. Well, what I understand is that Nutch's similarity is LinkRank that does somehow the same work as Google's PageRank and Solr 7.3.1 uses the BM25 similarity by default, and now I have to use the vector space model but I don't know if I have to implement it in both Nutch and Solr or only on Solr. Would you guide me please? ( If I'm understanding things wrong correct it for me please ).