diff --git a/.env.example b/.env.example
index ce65e25..39b591c 100644
--- a/.env.example
+++ b/.env.example
@@ -1 +1,4 @@
-DATABASE_URL=sqlite:////home/greybook/database/data.db
+# DATABASE_URL=sqlite:////home/greybook/database/data.db
+# MAIL_SERVER=smtp.example.com
+# MAIL_USERNAME=example
+# MAIL_PASSWORD=example-password
\ No newline at end of file
diff --git a/greybook/blueprints/admin.py b/greybook/blueprints/admin.py
index b0df347..0693c75 100644
--- a/greybook/blueprints/admin.py
+++ b/greybook/blueprints/admin.py
@@ -4,7 +4,7 @@
 from sqlalchemy import select
 
 from greybook.core.extensions import db
-from greybook.forms import CategoryForm, LinkForm, PostForm, SettingForm
+from greybook.forms import EditCategoryForm, LinkForm, NewCategoryForm, PostForm, SettingForm
 from greybook.models import Category, Comment, Link, Post
 from greybook.utils import allowed_file, random_filename, redirect_back
 
@@ -181,7 +181,7 @@ def manage_category():
 @admin_bp.route('/category/new', methods=['GET', 'POST'])
 @login_required
 def new_category():
-    form = CategoryForm()
+    form = NewCategoryForm()
     if form.validate_on_submit():
         name = form.name.data
         category = Category(name=name)
@@ -195,8 +195,8 @@ def new_category():
 @admin_bp.route('/category/<int:category_id>/edit', methods=['GET', 'POST'])
 @login_required
 def edit_category(category_id):
-    form = CategoryForm()
     category = db.session.get(Category, category_id) or abort(404)
+    form = EditCategoryForm(current_name=category.name)
     if category.id == 1:
         flash('You can not edit the default category.', 'warning')
         return redirect(url_for('blog.index'))
diff --git a/greybook/blueprints/blog.py b/greybook/blueprints/blog.py
index c1ab504..e7e6fac 100644
--- a/greybook/blueprints/blog.py
+++ b/greybook/blueprints/blog.py
@@ -67,7 +67,7 @@ def show_post(post_id):
         form = AdminCommentForm()
         form.author.data = current_user.name
         form.email.data = current_app.config['GREYBOOK_ADMIN_EMAIL']
-        form.site.data = url_for('.index')
+        form.site.data = url_for('.index', _external=True)
         from_admin = True
         reviewed = True
     else:
diff --git a/greybook/core/commands.py b/greybook/core/commands.py
index c31f97c..2be410f 100644
--- a/greybook/core/commands.py
+++ b/greybook/core/commands.py
@@ -3,7 +3,6 @@
 from sqlalchemy import select
 
 from greybook.core.extensions import db
-from greybook.lorem import fake_admin, fake_categories, fake_comments, fake_links, fake_posts, fake_replies
 from greybook.models import Admin, Category
 
 
@@ -66,6 +65,8 @@ def init_blog_command(username, password):
     @click.option('--reply', default=50, help='Quantity of replies, default is 50.')
     def lorem_command(category, post, comment, reply):
         """Generate fake data."""
+        from greybook.lorem import fake_admin, fake_categories, fake_comments, fake_links, fake_posts, fake_replies
+
         db.drop_all()
         db.create_all()
 
diff --git a/greybook/core/errors.py b/greybook/core/errors.py
index 606799d..2701634 100644
--- a/greybook/core/errors.py
+++ b/greybook/core/errors.py
@@ -17,4 +17,5 @@ def internal_server_error(error):
 
     @app.errorhandler(CSRFError)
     def handle_csrf_error(error):
-        return render_template('errors/400.html', description=error.description), 400
+        description = 'Session expired, return last page and try again.'
+        return render_template('errors/400.html', description=description), 400
diff --git a/greybook/forms.py b/greybook/forms.py
index 0493950..9aa1c52 100644
--- a/greybook/forms.py
+++ b/greybook/forms.py
@@ -47,7 +47,7 @@ def __init__(self, *args, **kwargs):
         self.category.choices = [(category.id, category.name) for category in categories]
 
 
-class CategoryForm(FlaskForm):
+class NewCategoryForm(FlaskForm):
     name = StringField('Name', validators=[DataRequired(), Length(1, 30)])
     submit = SubmitField()
 
@@ -56,6 +56,17 @@ def validate_name(self, field):
             raise ValidationError('Name already in use.')
 
 
+class EditCategoryForm(NewCategoryForm):
+    def __init__(self, current_name, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.current_name = current_name
+
+    def validate_name(self, field):
+        new_name = field.data
+        if new_name != self.current_name and db.session.scalar(select(Category).filter_by(name=new_name)):
+            raise ValidationError('Name already in use.')
+
+
 class CommentForm(FlaskForm):
     author = StringField('Name', validators=[DataRequired(), Length(1, 30)])
     email = StringField('Email', validators=[DataRequired(), Email(), Length(1, 254)])
diff --git a/greybook/templates/base.html b/greybook/templates/base.html
index 3e59326..6e83508 100644
--- a/greybook/templates/base.html
+++ b/greybook/templates/base.html
@@ -11,7 +11,7 @@
       href="{{ url_for('static', filename='css/%s.min.css' % request.cookies.get('theme', 'default')) }}">
   <link rel="stylesheet" href="{{ url_for('static', filename='css/main.css') }}">
   {% if admin.custom_css %}
-  <style>{{ admin.custom_css | safe }}</style>
+  <style>{{ admin.custom_css|safe }}</style>
   {% endif %}
   {% endblock head %}
 </head>
@@ -82,7 +82,7 @@
       <p class="float-start">
         <small>
           {% if admin.custom_footer %}
-          {{ admin.custom_footer | safe }}
+          {{ admin.custom_footer|safe }}
           {% else %}
           &copy; 2024
           <a href="{{ url_for('blog.index') }}">{{ admin.name }}</a> ·
@@ -110,7 +110,7 @@
   <script src="{{ url_for('static', filename='js/dayjs/plugin/localizedFormat.js') }}"></script>
   <script src="{{ url_for('static', filename='js/main.js') }}"></script>
   {% if admin.custom_js %}
-  <script>{{ admin.custom_js | safe }}</script>
+  <script>{{ admin.custom_js|safe }}</script>
   {% endif %}
   {% endblock %}
 </body>
diff --git a/greybook/templates/errors/400.html b/greybook/templates/errors/400.html
index b0ac9ee..27ce37b 100644
--- a/greybook/templates/errors/400.html
+++ b/greybook/templates/errors/400.html
@@ -8,7 +8,7 @@ <h1>400 Error</h1>
 </div>
 <div class="row">
   <div class="col-sm-8">
-    <p>{{ description | default('Bad Request') }}</p>
+    <p>{{ description|default('Bad Request') }}</p>
   </div>
   <div class="col-sm-4 sidebar">
     {% include 'blog/_sidebar.html' %}
diff --git a/greybook/templates/errors/404.html b/greybook/templates/errors/404.html
index abd45bb..fcfe614 100644
--- a/greybook/templates/errors/404.html
+++ b/greybook/templates/errors/404.html
@@ -8,7 +8,7 @@ <h1>404 Error</h1>
 </div>
 <div class="row">
   <div class="col-sm-8">
-    <p>{{ description | default('Page Not Found') }}</p>
+    <p>{{ description|default('Page Not Found') }}</p>
   </div>
   <div class="col-sm-4 sidebar">
     {% include 'blog/_sidebar.html' %}
diff --git a/greybook/templates/errors/500.html b/greybook/templates/errors/500.html
index 190d670..c65e2ed 100644
--- a/greybook/templates/errors/500.html
+++ b/greybook/templates/errors/500.html
@@ -8,7 +8,7 @@ <h1>500 Error</h1>
 </div>
 <div class="row">
   <div class="col-sm-8">
-    <p>{{ description | default('Internal Server Error') }}</p>
+    <p>{{ description|default('Internal Server Error') }}</p>
   </div>
   <div class="col-sm-4 sidebar">
     {% include 'blog/_sidebar.html' %}
diff --git a/tests/test_admin.py b/tests/test_admin.py
index a93c2e6..5f6a32c 100644
--- a/tests/test_admin.py
+++ b/tests/test_admin.py
@@ -214,6 +214,14 @@ def test_edit_category(self):
         self.assertIn('Category updated.', data)
         self.assertIn('Life', data)
         self.assertNotIn('Tech', data)
+        # test name already in use
+        response = self.client.post('/admin/category/2/edit', data=dict(name='Test Category'), follow_redirects=True)
+        data = response.get_data(as_text=True)
+        self.assertIn('Name already in use.', data)
+        # test use current name
+        response = self.client.post('/admin/category/2/edit', data=dict(name='Life'), follow_redirects=True)
+        data = response.get_data(as_text=True)
+        self.assertIn('Category updated.', data)
 
     def test_delete_category(self):
         category = Category(name='Tech')