issue: Prevent Click Jacking

This addresses a vulnerability where there was no `X-Frame-Options` header
which could potentially allow click jacking. This adds the
`X-Frame-Options: SAMEORIGIN` header so it will remove any chance of click
jacking. According to Mozilla Developer Docs:
```
SAMEORIGIN
The page can only be displayed in a frame on the same origin as the page
itself.
```