Cleanup router setup

[steeevin88]

being nitpicky but i think these lines are a bit messy:

SCEvents/cmd/server/main.go

Lines 39 to 61 in 279d801

	r := gin.Default()
	config := cors.DefaultConfig()
	config.AllowOrigins = []string{clientURL}
	config.AllowCredentials = true
	config.AddAllowHeaders("Authorization")
	r.Use(cors.New(config))
	r.GET("/ping", func(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
	"message": "response",
	})
	})
	events := r.Group("/events")
	{
	events.GET("/", handlers.GetEvents)
	events.GET("/:id", handlers.GetEventByID)
	events.POST("/", handlers.CreateEvent)
	events.DELETE("/:id", handlers.DeleteEventByID)
	}
	r.Run(":8002")

as we add more handlers and stuff it might be a lot of code. and main.go is ideally clean as it's the "main entrypoint" for our server... so let's clean this up. ideally it's just a "setupRouter" function that returns the router for us...

[ ] create a new file in the main package --> router.go
[ ] create a new setupRouter() function that takes in the config create in #32 and sets the router up. this includes creating the gin router, setting up cors, and defining all handlers
[ ] update main.go to import this function; it should be a clean initialization now:

r := setupRouter(cfg)
r.Run(":" + cfg.Port)