[ISSUE-48] Adding the ability to repost another user's post.

For Issue #48

This is just a really rough first pass at Issue 48.  Please nitpick my go/ember code as Im just learning both.  I'm also ignoring the linked Issue 47 on how we want to do discovery or cross linking between posts. Right now Im just doing a super rudimentary approach where I store the original post details in the new post. I don't do any sort of linking to the original author or post or a way to follow them. Before this is accepted I'd like to get a plan together for that.

Other possible improvements/thoughts:

Show the post you are reposting in a modal instead of just a confirm box.

If you are also subscribed to the original poster, how should we handle this? Do we just show the original poster's message and then also have some styling showing how many other people that you follow reposted it or do we show the message twice (or more) like I am doing now?