Update readme to reflect changes

Author: btd

README.md

@@ -2,42 +2,39 @@
 
 Sharp based implementation of perceptual hash (phash) algorithm described [there](http://www.hackerfactor.com/blog/?/archives/432-Looks-Like-It.html).
 
+## Installation
+
+```sh
+yarn add sharp sharp-phash
+# or
+npm i sharp sharp-phash
+```
+
+You **must** install **sharp** yourself.
+
 ## How to use
 
 ```js
-'use strict';
+"use strict";
 
-const fs = require('fs');
-const Promise = require('bluebird');
+const fs = require("fs");
+const Promise = require("bluebird");
 
-const assert = require('assert');
+const assert = require("assert");
 
-const phash = require('sharp-phash');
-const dist = require('sharp-phash/distance');
+const phash = require("sharp-phash");
+const dist = require("sharp-phash/distance");
 
-const img1 = fs.readFileSync('./Lenna.png');
-const img2 = fs.readFileSync('./Lenna.jpg');
-const img3 = fs.readFileSync('./Lenna-sepia.jpg');
+const img1 = fs.readFileSync("./Lenna.png");
+const img2 = fs.readFileSync("./Lenna.jpg");
+const img3 = fs.readFileSync("./Lenna-sepia.jpg");
 
-Promise.all([
-  phash(img1),
-  phash(img2),
-  phash(img3)
-])
-  .then(([hash1, hash2, hash3]) => {
+Promise.all([phash(img1), phash(img2), phash(img3)]).then(
+  ([hash1, hash2, hash3]) => {
     // hash returned is 64 characters length string with 0 and 1 only
     assert(dist(hash1, hash2) < 5);
     assert(dist(hash2, hash3) < 5);
     assert(dist(hash3, hash1) < 5);
-  });
-```
-
-## Your own sharp version
-
-```js
-const sharp = require('sharp');
-const phash = require('sharp-phash');
-
-phash(..., { sharp })
-
+  }
+);
 ```