updated readme

Search_Engine/README.md

@@ -1,6 +1,6 @@
-Python Program to search through various documents and return the documents containing the search term.
+Python Program to search through various documents and return the documents containing the search term. Algorithm involves using a reverse index to store each word in each document where a document is defined by an index. To get the document that contains a search term, we simply find an intersect of all the words in the search term, and using the resulting indexes, retrieve the document(s) that contain these words
 
-To see in action, run
+To use directly, run
 
 ```python3 backend.py```