Switch for turning caching on/off for /users/{userid}

[AllisonBC]

Closes #249
WHAT IT DOES:
Feature switch to turn on and off caching for /users/{user_id}

TO TEST:
Set up

1. Be sure that you are able to use the VS Code debugger. Troubleshooting this alone was both difficult and time consuming.

2. Install the Azure Cache extension in VS Code.
   

3. functions\local.settings.json file set up:
   a. Need values: "ENV_DATABASE_CONNECTION_STRING", "ENV_REDIS_KEY", "ENV_REDIS_HOST", "ENV_REDIS_PORT"
   b. Add value: "CACHE_TOGGLE": "true"

4. Postman is helpful for making the requests.

Testing

5. Run the debugger on Python Functions.

6. In Postman or browser make a get request for user with id 1
   Terminal:
   
   VS Code Azure extension in Caches:
   (click on users:all)
   

7. Return to functions\local.settings.json file, set "CACHE_TOGGLE": "false" and save.
   NOTE: At this point, I had to exit and reopen VSCode entirely to get the debugger to acknowledge the change in this value.

8. Run the debugger on Python Functions.

9. In Postman or browser make a get request for user with id 10
   Terminal:
   

VS Code Azure extension in Caches:

Running this process a third time with the toggle set to "true" will result in a cache clear, and the user you requested being added to the cache.

TIME SPENT:

Date	Description	Time
3/9	Meet with Johart	1.5 hrs
3/12	Review class lecture	1 hrs
3/12	Code Review and Development	2 hrs
3/15	Troubleshooting debugger issues	1 hrs
3/18	Debugging	1 hrs
3/5- 3/18	Record keeping	1 hrs

[unicornsleuth]

The key should be "users:{userId}" - don't use the universal key - that might be a leftover from other code. You want to build the key each time you cache, by passing in the userId, so you can make something this redis_key = "users:" + str(userId) and use that to set/fetch the catch

[unicornsleuth]

Blocking: the redis key for each of these must be "users:{userId}" not "users:all"
Requested: verify the CACHE_TOGGLE key. Your code works and is clean & easy to read, but my PRs for the cache toggle on /users and /users/{userId}/tasks have already been merged, so they won't work together.

[unicornsleuth]

Ok so I just saw that Johart's PR already went through with his CACHE_TOGGLE values as true/false, and then I just checked in Azure and it's been changed to true now, so I guess I was just out of the loop when that got changed and I'll have to make a PR to change my code. Disregard my comments on that note!

[unicornsleuth]

There are bugs here - I'm not sure exactly what it is, but when the cache is set to True, it still says caching is set to false in the output. I stepped through it and it looked like it was getting a None result and throwing errors... It could have to do with the thing I pointed out, but I'm not sure.

[unicornsleuth]

If you just remove the == "true" this will work better - sometimes it is True, sometimes true, in the Azure function app, but both of those will evaluate to True if you don't tell it to compare Strings. If that makes sense. So everywhere you have if CACHE_TOGGLE == "true": to just if CACHE_TOGGLE: