Add first half of login process

src/jade/includes/_header.jade

@@ -12,6 +12,7 @@
 
     .addthis_sharing_toolbox
     .divider.bottom
+        .login: a(href="/login") Login
 
     .navBar
         a(data-page="home", href="/")

src/jade/templates/login_page.jade

@@ -0,0 +1,38 @@
+//-
+//- Crafting Guide - login_page.jade
+//-
+//- Copyright (c) 2015 by Redwood Labs
+//- All rights reserved.
+//-
+
+.view__login_page
+    .two-thirds-content.hideable.service-up
+        img.float-right(src="/images/github-login-large.png")
+        h1 Login with GitHub
+        p.
+            Use your GitHub credentials to login and make changes on Crafting Guide. No GitHub account? Don't worry, you
+            can get one for free. <a class="read-more" href="#">read more...</a>
+        .read-more-content.slideable.closed
+            p.
+                All changes you make on the site get submitted directly to our GitHub repo, and then published through
+                the same automated deployment process as changes made by anyone else. That way, anyone can contribute
+                easily: whether developer or end user.
+            p.
+                To log in, we redirect you to GitHub's site, and once you're signed in, they'll send you back here. We
+                never see your credentials, and only get the minimum set of permissions necessary to submit changes to
+                the Crafting Guide repo on your behalf.
+            p.
+                GitHub offers free accounts, so even if you don't already have one, you've got nothing to lose!
+
+        .actions
+            button.huge Login with GitHub
+
+        .clear
+
+    .two-thirds-content.hideable.hidden.service-down
+        h1 Sorry!
+        p.
+            Our interactive editing service is down right now, but you can always submit a pull request over at
+            the <a href="https://github.com/andrewminer/crafting-guide">Crafting Guide GitHub Repository</a>. We'll have
+            the editing service back up soon!
+