Add migrate nav item to pages and update migrate document

client/homebrew/navbar/migrate.navitem.jsx

@@ -0,0 +1,13 @@
+const React = require('react');
+const Nav = require('naturalcrit/nav/nav.jsx');
+
+module.exports = function(props){
+	return <Nav.item
+		className='migrate'
+		newTab={false}
+		href='/migrate'
+		color='blue'
+		icon='fas fa-route'>
+		migrate
+	</Nav.item>;
+};