docs: add install build and test guide (#215)

* docs: add install build and test guide

* docs: remove install build and test guides

* docs: add installation guide

README.md

@@ -8,6 +8,14 @@ The Mercury Parser module powers the [Mercury Parser API](https://mercury.postli
 
 ## How? Like this.
 
+### Installation
+
+```bash
+yarn add mercury-parser
+```
+
+### Usage
+
 ```javascript
 import Mercury from 'mercury-parser';
 
@@ -46,6 +54,9 @@ If you'd like to write a custom parser for a site, [here's how](src/extractors/c
 [![All Contributors](https://img.shields.io/badge/all_contributors-4-orange.svg?style=flat-square)](#contributors)
 
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
+
 | [<img src="https://avatars.githubusercontent.com/u/64131?v=3" width="100px;"/><br /><sub>Adam Pash</sub>](http://adampash.com)<br />📝 [💻](https://github.com/postlight/readability-parser/commits?author=adampash) [📖](https://github.com/postlight/readability-parser/commits?author=adampash) 💡 | [<img src="https://avatars.githubusercontent.com/u/19412836?v=3" width="100px;"/><br /><sub>Toy Vano</sub>](https://github.com/spiffytoy)<br />[💻](https://github.com/postlight/readability-parser/commits?author=spiffytoy) | [<img src="https://avatars.githubusercontent.com/u/183608?v=3" width="100px;"/><br /><sub>Drew Bell</sub>](droob.org)<br />[💻](https://github.com/postlight/readability-parser/commits?author=droob) | [<img src="https://avatars.githubusercontent.com/u/305901?v=3" width="100px;"/><br /><sub>Jeremy Mack</sub>](https://twitter.com/mutewinter)<br />[💻](https://github.com/postlight/readability-parser/commits?author=mutewinter) |
-| :---: | :---: | :---: | :---: |
+| :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------: |
+
+
 <!-- ALL-CONTRIBUTORS-LIST:END -->

src/extractors/custom/README.md

@@ -185,7 +185,7 @@ For our New Yorker example, we're going to use [this story](http://www.newyorker
 When the generator script completes, you'll be prompted to run:
 
 ```bash
-yarn watch:test -- www.newyorker.com
+yarn watch:test www.newyorker.com
 ```
 
 This will run the tests for the parser you just generated, which should fail (which makes sense — you haven't written it yet!). Your goal now is to follow the instructions in the generated `www.newyorker.com/index.test.js` and `www.newyorker.com/index.js` files until they pass!
@@ -253,7 +253,7 @@ AssertionError: 'Hacking, Cryptography, and the Countdown to Quantum Computing'
   'Schrödinger’s Hack';
 ```
 
-When Mercury generated our test, it took a guess at the page's title, and in this case, it got it wrong. So update the test with thte title we expect, save it, and your test should pass!
+When Mercury generated our test, it took a guess at the page's title, and in this case, it got it wrong. So update the test with the title we expect, save it, and your test should pass!
 
 ### Step 3: Speed it up