Add twitter meta tags to head

[PaulSearcy]

Noticed that we don't have twitter meta tags set up on the site for the group's twitter account @desmoinesjs or open graph tags either.

Here is an example implementation:

<meta name="twitter:site" content="@desmoinesjs ">
<meta name="twitter:creator" content="@desmoinesjs ">
<meta name="twitter:image" content="https://dsmjs.com/img/dsmjs-logo.png">
<meta property="og:type" content="website" />
<meta property="og:url" content="https://dsmjs.com/">
<meta property="og:image" content="https://dsmjs.com/img/dsmjs-logo.png" />
<meta property="og:image:type" content="image/png" />
<meta property="og:image:alt" content="Des Moines JavaScript Logo" />

Ref:
Twitter - https://dev.twitter.com/cards/markup
Open Graph - https://developers.facebook.com/docs/sharing/webmasters/ or http://ogp.me/