Simplify controller functions

[jpahm]

Currently the controller functions are written in an over-complicated format, like so:

func CourseAll() gin.HandlerFunc {
	return func(c *gin.Context) {
		// Controller code here...
	}
}

This is over-complicated and cluttered, since the above code could be easily rewritten like so:

func CourseAll(c *gin.Context) {
	// Controller code here...
}

We should seek to simplify all of the controller code like shown -- code using the controllers will need to be adjusted accordingly.

[mikehquan19]

Hi! I'm new to Go and Mongo. Can I get assigned to this task ?

[jpahm]

Hi! I'm new to Go and Mongo. Can I get assigned to this task ?

Yes you can, it's all yours!

[jpahm]

Closed via #219