feat: pop out loading modal once register button is clicked

src/Male.js

@@ -86,6 +86,7 @@ class Male extends React.Component {
 
   handleClick(program_name) {
     const program_type = '男子';
+    this.openModal('加载中', '');
     fetch('/register', {
       method: 'Post',
       body: JSON.stringify({
@@ -96,8 +97,10 @@ class Male extends React.Component {
       .then(response => response.json())
       .then(json => {
         if (json.result === 'success') {
+          this.handleCloseModal();
           this.openModal('成功', '成功报名男子项目' + program_name);
         } else {
+          this.handleCloseModal();
           this.openModal('失败', '报名男子项目' + program_name + '时失败');
         }
       });