Added travis config

Author: marcveens

.travis.yml

@@ -0,0 +1,15 @@
+language: node_js
+
+node_js:
+  - "12.14.0"
+
+install:
+  - npm install
+
+cache:
+  directories:
+    - node_modules
+
+script:
+  - npm run lint
+  - npm run build

README.md

@@ -1,4 +1,7 @@
 # react-context-mutex
+[![npm version](https://badgen.net/npm/v/react-context-mutex)](https://www.npmjs.com/package/react-context-mutex)
+[![Build Status](https://travis-ci.com/marcveens/react-context-mutex.svg?branch=master)](https://travis-ci.com/marcveens/react-context-mutex)
+
 A mutex implementation using React and React context. It will prevent a function from running multiple times, until you allow it to run again. 
 
 I created this because I wanted to prevent a fetch from running multiple times after implementing a custom hook in multiple components. The custom hook had a `useEffect` which ran the fetch function.