Alpha release of CTFd v3. 

# 3.0.0a1 / 2020-07-01

**General**

- CTFd is now Python 3 only
- Render markdown with the CommonMark spec provided by `cmarkgfm`
- Render markdown stripped of any malicious JavaScript or HTML.
  - This is a significant change from previous versions of CTFd where any HTML content from an admin was considered safe.
- Inject `Config`, `User`, `Team`, `Session`, and `Plugin` globals into Jinja
- User sessions no longer store any user-specific attributes.
  - Sessions only store the user's ID, CSRF nonce, and an hmac of the user's password
  - This allows for session invalidation on password changes
- The user facing side of CTFd now has user and team searching
- GeoIP support now available for converting IP addresses to guessed countries

**Admin Panel**

- Use EasyMDE as an improved description/text editor for Markdown enabled fields.
- Media Library button now integrated into EasyMDE enabled fields
- VueJS now used as the underlying implemen...