Add support for events

:bomb: WIP

This PR is to add support for listing events on the 24pullrequest website. I am opening up the PR early to get some early direction and feedback.

### To do -

- [x] Add event model and attributes
- [x] Add map with events
- [ ] Restrict `event#new` and `event#edit` to logged in users
- [ ] Move all content into the locale files
- [ ] Add events link to the homepage
- [ ] Convert html to haml **requesting support**
- [x] Add datetime picker

![image](https://cloud.githubusercontent.com/assets/1238468/4760789/cc23f92e-5af2-11e4-8160-be90cdb70e6a.png)

![image](https://cloud.githubusercontent.com/assets/1238468/4760809/f0ca6b46-5af2-11e4-833e-7dd0776987fe.png)

![image](https://cloud.githubusercontent.com/assets/1238468/4760817/fc0ac3a2-5af2-11e4-8035-8c49d56a3754.png)




@adambutler I'm not a fan of this, bower doesn't have any concept of locking version numbers meaning every time travis installs dependencies the contents of `rails-assets-datetimepicker` could change, instead lets just vendor a known working version of datetimepicker instead.