implemented client side filters, mobile first styling and modals for articles

backend/app/schema.sql

@@ -4,11 +4,11 @@
 CREATE TABLE IF NOT EXISTS news (
     id          INTEGER PRIMARY KEY AUTOINCREMENT,
     title       TEXT NOT NULL,
-    description TEXT,
+    summary     TEXT,
     url         TEXT NOT NULL,
     published   TIMESTAMP NOT NULL,
     country     TEXT NOT NULL,
-    created_at  TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+    created_at  INTEGER DEFAULT (strftime('%s', 'now'))
 );
 
 -- Index for faster queries on published date