docs: update README.md (#80)

The original clone command requires you to setup keys with github, which of course is doable, but adds to the burden of a newbie to try your great framework.

README.md

@@ -6,7 +6,7 @@ This app accompanies the Ionic 2 component documentation.
 
 ### Installation & Development
 
-1. clone this repo: `git clone git@github.com:driftyco/ionic-preview-app.git`
+1. clone this repo: `git clone https://github.com/driftyco/ionic-preview-app.git`
 2. `cd ionic-preview-app`
 3. `npm install`
 4. run `ionic serve` from a terminal
@@ -24,4 +24,4 @@ This app accompanies the Ionic 2 component documentation.
 
 ### Updating ionic-site
 
-`ionic-site` will automatically update on every commit to the master branch of this repo.
+`ionic-site` will automatically update on every commit to the master branch of this repo.