Mark 3.1.0 (#1634)

# 3.1.0 / 2020-09-08

**General**

- Loosen team password confirmation in team settings to also accept the team captain's password to make it easier to change the team password
- Adds the ability to add custom user and team fields for registration/profile settings.
- Improve Notifications pubsub events system to use a subscriber per server instead of a subscriber per browser. This should improve the reliability of CTFd at higher load and make it easier to deploy the Notifications system

**Admin Panel**

- Add a comments functionality for admins to discuss challenges, users, teams, pages
- Adds a legal section in Configs where users can add a terms of service and privacy policy
- Add a Custom Fields section in Configs where admins can add/edit custom user/team fields
- Move user graphs into a modal for Admin Panel

**API**

- Add `/api/v1/comments` to manipulate and create comments

**Themes**

- Make scoreboard caching only cache the score table instead of the entire page. This is done by caching the specific template section. Refer to #1586, specifically the changes in `scoreboard.html`.
- Add rel=noopener to external links to prevent tab napping attacks
- Change the registration page to reference links to Terms of Service and Privacy Policy if specified in configuration

**Miscellaneous**

- Make team settings modal larger in the core theme
- Update tests in Github Actions to properly test under MySQL and Postgres
- Make gevent default in serve.py and add a `--disable-gevent` switch in serve.py
- Add `tenacity` library for retrying logic
- Add `pytest-sugar` for slightly prettier pytest output
- Add a `listen()` method to `CTFd.utils.events.EventManager` and `CTFd.utils.events.RedisEventManager`.
  - This method should implement subscription for a CTFd worker to whatever underlying notification system there is. This should be implemented with gevent or a background thread.
  - The `subscribe()` method (which used to implement the functionality of the new `listen()` function) now only handles passing notifications from CTFd to the browser. This should also be implemented with gevent or a background thread.

serve.py

@@ -1,4 +1,3 @@
-from CTFd import create_app
 import argparse
 
 parser = argparse.ArgumentParser()
@@ -6,7 +5,20 @@ parser.add_argument("--port", help="Port for debug server to listen on", default
 parser.add_argument(
     "--profile", help="Enable flask_profiler profiling", action="store_true"
 )
+parser.add_argument(
+    "--disable-gevent",
+    help="Disable importing gevent and monkey patching",
+    action="store_false",
+)
 args = parser.parse_args()
+if args.disable_gevent:
+    print(" * Importing gevent and monkey patching. Use --disable-gevent to disable.")
+    from gevent import monkey
+
+    monkey.patch_all()
+
+# Import not at top of file to allow gevent to monkey patch uninterrupted
+from CTFd import create_app
 
 app = create_app()