[FEAT] Refactor API main file and models

This commit refactors the `main.go` file in the API directory, as well as the related models in the `models.go` file. The changes include:

- Reordering imports and removing unnecessary imports
- Fixing error messages to be more descriptive
- Handling database connections more efficiently with deferred closures
- Handling errors and returning appropriate error responses
- Adding proper JSON bindings for POST requests
- Adding new views in the database scripts for aggregated statistics and daily user statistics

No changes were made to imports and requires.

1 files changed, 8 insertions, 5 deletions

diff --git a/fe/src/lib/forms/AddForm.svelte b/fe/src/lib/forms/AddForm.svelte
index f22e5f4..4520b1b 100644
--- a/fe/src/lib/forms/AddForm.svelte
+++ b/fe/src/lib/forms/AddForm.svelte
@@ -34,20 +34,23 @@
         dispatch("close");
     }
 
-    async function handleSubmitStat() {
-        const response = await fetch("http://localhost:8080/api/v1/stats/", {
+    async function handleSubmitStat()
+    {
+        const { date, quantity } = statistic;
+        await fetch("http://localhost:8080/api/v1/stats/", {
             method: "POST",
             headers: {
                 Authorization: `Bearer ${$token}`
             },
             body: JSON.stringify({
-                date: new Date(),
-                user_id: 1,
-                quantity: 3
+                date: new Date(date),
+                user_id: 2,
+                quantity
             })
         });
         dispatch("submit");
     }
+
 </script>
 
 <dialog {open} on:submit={handleSubmitStat}>