Update README.md

Author: vzhong

README.md

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 # WikiSQL
 
+[![Build Status](https://travis-ci.org/salesforce/WikiSQL.svg?branch=master)](https://travis-ci.org/salesforce/WikiSQL)
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 A large crowd-sourced dataset for developing natural language interfaces for relational databases. WikiSQL is the dataset released along with our work [Seq2SQL: Generating Structured Queries from Natural Language using Reinforcement Learning](http://arxiv.org/abs/1709.00103).