Fix resume uploads, improve job application / resume upload experience. WIP-327

Addresses issue in: https://assembly.com/coderwall/wips/327

Fixed and improved experience for uploading resumes and applying to a job.

### Before Applying
![team_teampro___coderwall_com](https://cloud.githubusercontent.com/assets/197892/3902132/c77fe6a2-22b8-11e4-98fc-74992606c8de.png)

### Upload your resume
![apply-upload](https://cloud.githubusercontent.com/assets/197892/3902109/1c165292-22b8-11e4-84a7-b1142d00c5a8.png)

### Upload in progress
![apply-uploading](https://cloud.githubusercontent.com/assets/197892/3902110/1c1b1bba-22b8-11e4-9d84-a97180817718.png)

### Uploaded successfully
![apply-uploaded](https://cloud.githubusercontent.com/assets/197892/3902108/1c162fce-22b8-11e4-9a49-cf3e4c06d1f3.png)

### Application submitted - flash message
![apply-success](https://cloud.githubusercontent.com/assets/197892/3902106/1c141c52-22b8-11e4-8418-29f5f78a59b3.png)

### Resume already submitted
![apply-prev](https://cloud.githubusercontent.com/assets/197892/3902107/1c159b90-22b8-11e4-83b1-3f0ca98f6140.png)

This action can be moved into the user controller.
It missing routing and controller test.