Update README.md

Author: curquiza

README.md

@@ -105,7 +105,7 @@ fn main() { block_on(async move {
     // Create a client (without sending any request so that can't fail)
     let client = Client::new("http://localhost:7700", "masterKey");
 
-    // Get the index called "movies"
+    // An index is where the documents are stored.
     let movies = client.get_or_create("movies").await.unwrap();
 
     // Add some movies in the index