Added FAQ, install and API sections (#5)

Added FAQ, install and API sections

readme.md

@@ -1,4 +1,89 @@
 # get-pkg-prop
 > Pass a key name, get a value from package.json
 
-![travis CI build status](https://travis-ci.org/servexyz/get-pkg-prop.svg?branch=master)
+![travis CI build status](https://travis-ci.org/servexyz/get-pkg-prop.svg?branch=master)
+
+## FAQ
+<details><summary>Why</summary>
+
+<ul>
+<li>Initially motivated by the desire to print package version</li>
+<li>Destructuring rocks. <code>const { version } = require('./package.json')</code>. 
+<ul> 
+<li>Require's caching makes it difficult to use with development. Read more <a href="https://goenning.net/2016/04/14/stop-reading-json-files-with-require/">here </a>
+<li>Unfortunately, Webpack throws a critical warning when using dynamic requires in certain circumstances (see <a href="https://github.com/TooTallNate/node-bindings/issues/42">example here</a>). And while there are supposed fixes, I wanted to avoid the cluster altogether since I use webpack in almost every javascript project</li>
+</li>
+</ul>
+<li>
+I wanted to have a more diverse API for different situations. 
+<ul><li>Module self-testing? Call <code>get-pkg-prop("property")</code> without specifying package. </li>
+
+<li>Testing child-module? Call <code>get-pkg-prop("property", "/sub/path/to/package.json")</code> with package path specified.</li> 
+
+<li>Mock testing? Create a mock package JSON object and call it with <code>get-pkg-prop("property", myPkgObj)</code>
+</li>
+</ul>
+
+</li>
+</ul>
+</details>
+
+## Getting Started
+
+**Install**
+```
+npm install get-pkg-prop -S
+```
+
+**Add to source**
+```
+import { getPkgProp } from 'get-pkg-prop
+```
+
+**Use**
+```js
+getPkgProp("version") // x.y.z
+```
+
+
+## API
+
+<details><summary> <code>getPkgProp(szProperty)</code></h4></summary>
+<hr />
+<b>Where</b>
+
+* *szProperty* is the name of the property. 
+
+<b>How</b>
+
+* This uses [pkg-up](https://github.com/sindresorhus/pkg-up) to find the closest `package.json`. 
+
+<hr />
+</details>
+
+<details><summary> <code>getPkgProp(szProperty, szPathToPackageJSON)</code></h4></summary>
+<hr />
+<b>Where</b>
+
+* *szProperty* is the name of the property. 
+* *szPathToPackageJSON* is the path to either your package.json file or the directory which contains the package.json file. 
+
+<b>Why</b>
+
+* Specifying the path allows you to access the package of sub-modules or installed dependencies.
+
+<hr />
+</details>
+
+<details><summary> <code>getPkgProp(szProperty, oPackageJSON)</code></h4></summary>
+<hr />
+<b>Where</b>
+
+* *szProperty* is the name of the property. 
+* *oPackageJSON* is the JSON object which contains your package
+
+<b>Why</b>
+
+* I added this for mock testing inline package objects. 
+<hr />
+</details>