Add function that will pull API and Implement API changes at EOD.

[JAYKAY2291]

Summary

Function needed that will pull API at the end of each day and implement price changes.

Things out of Scope

This function is independent of adding buy orders which is called out in issue #145, although this function will be working in tandem with the buy order function.

Criteria for Completion

This should be a bulleted list of items that, if satisfied, would result in an acceptably complete Pull Request. Be as specific as you need to be. For example:

• At the end of each day, API should be pulled, and displayed stock prices should be changed.
• This feature must be available for all users to view.
• Add a test proving that it works

[abachman]

related issue in #56