feat: add basic csv loading

src/root.zig

@@ -1,10 +1,7 @@
 const std = @import("std");
+const csv = @import("csv.zig");
 const testing = std.testing;
 
-export fn add(a: i32, b: i32) i32 {
-    return a + b;
-}
-
-test "basic add functionality" {
-    try testing.expect(add(3, 7) == 10);
+test {
+    testing.refAllDecls(@This());
 }