Merge pull request #431 from jielinxu/0.6.0

[skip ci] Add README for docs file

docs/README.md

+# Docs
+
+This repository contains test reports on the search performance of different index types on standalone Milvus.
+
+The tests are run on [SIFT1B dataset](http://corpus-texmex.irisa.fr/), and provide results on the following measures:
+
+- Query Elapsed Time: Time cost (in seconds) to run a query. 
+
+- Recall: The fraction of the total amount of relevant instances that were actually retrieved.
+
+Test variables are `nq` and `topk`.