迁移数据库为postgresql

templates/study/login.html

@@ -0,0 +1,19 @@
+登录页面
+<br>
+<form method="post" action="./">
+用户名:
+<br>
+<input type="text" name="username" id="lower" required>
+<br>
+密码:
+<br>
+<input type="password" name="passwd" required>
+<br>
+<button type="submit">登录</button>
+</form>
+
+<script>
+    document.getElementById('lower').addEventListener('input', function() {
+        this.value = this.value.toLowerCase();
+    });
+</script>