Change store credit balance to budget remaining

[frediansimanjuntak]

Description

Change store credit balance to budget remaining on my account page at master branch

Trello link: https://trello.com/c/M4636ztQ

Remarks

• No remarks

Testing

• Testing on my account page

Checklist:

• The code follows the conventions of Rails and this project (eg. naming of routes and variables)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have tested my code thoroughly
• The code does not break existing functionality
• I have added instructions and data required to test the code
• I have tested the changes on the front-end on Chrome, Firefox and IE