Add option for uploading anonymously

Migration (SQLite):
`ALTER TABLE problem ADD COLUMN is_anonymous BOOLEAN;`

models/problem.js

@@ -171,6 +171,7 @@ let model = db.define('problem', {
       key: 'id'
     }
   },
+  is_anonymous: { type: Sequelize.BOOLEAN },
 
   description: { type: Sequelize.TEXT },
   input_format: { type: Sequelize.TEXT },
@@ -216,6 +217,7 @@ class Problem extends Model {
       title: '',
       user_id: '',
       publicizer_id: '',
+      is_anonymous: false,
       description: '',
 
       input_format: '',

modules/problem.js

@@ -315,6 +315,7 @@ app.post('/problem/:id/edit', async (req, res) => {
     problem.output_format = req.body.output_format;
     problem.example = req.body.example;
     problem.limit_and_hint = req.body.limit_and_hint;
+    problem.is_anonymous = (req.body.is_anonymous === 'on');
 
     // Save the problem first, to have the `id` allocated
     await problem.save();

views/problem.ejs

@@ -85,26 +85,28 @@ if (contest) {
           <% } %>
         </div>
         <div class="ui large labels" style="float: right; vertical-align: middle">
-          <div class="ui basic image label" style="font-size: 1.1em; margin-right: 0;">
+          <div class="ui basic image label" style="font-size: 1.1em; margin-right: 0.3em;">
+            <% if (problem.is_anonymous) { %>
+              <img src="<%= syzoj.utils.gravatar('', 64) %>">
+              <a>匿名用户</a>
+            <% } else { %>
               <img src="<%= syzoj.utils.gravatar(problem.user.email, 64) %>">
               <a href="<%= syzoj.utils.makeUrl(['user', problem.user_id]) %>"><%= problem.user.username %></a>
+            <% } %>
             <div class="detail">上传</div>
           </div>
           <% if (problem.is_public) {  %>
+            <div class="ui basic image label" style="font-size: 1.1em; margin-right: <% if (problem.allowedEdit || problem.allowedManage) { %>0.3em<% } else { %>0<% } %>;">
               <% if (problem.publicizer) { %>
-              <div class="ui basic image label" style="font-size: 1.1em; margin-left: 0.3em; margin-right: 0;">
                 <img src="<%= syzoj.utils.gravatar(problem.publicizer.email, 64) %>">
                 <a href="<%= syzoj.utils.makeUrl(['user', problem.publicizer_id]) %>"><%= problem.publicizer.username %></a>
-                <div class="detail">公开</div>
-              </div>
               <% } else { %>
-              <div class="ui basic image label" style="font-size: 1.1em; margin-left: 0.3em; margin-right: 0;">
                 <img src="<%= syzoj.utils.gravatar('', 64) %>">
                 <a>LibreOJ 管理员</a>
+              <% } %>
               <div class="detail">公开</div>
             </div>
           <% } %>
-          <% } %>
         </div>
       <% } %>
     </div>

views/problem_edit.ejs

@@ -43,6 +43,11 @@
               <option value="<%= tag.id %>" selected><%= tag.name %></option>
             <% } %>
           </select>
+          <div class="ui <% if (problem.is_anonymous) { %>checked <% } %>checkbox" style="margin-top: 15px; ">
+            <input <% if (problem.is_anonymous) { %>checked=""<% } %> name="is_anonymous" type="checkbox">
+            <label><strong>匿名上传</strong></label>
+            <p style="margin-top: 5px; ">选择后，上传者的用户名将不在题目页面中显示。</p>
+          </div>
         </div>
       </div>
       <div class="ui bottom attached tab segment" data-tab="preview" id="preview">