fix: add seo

Author: qiwihui

Gemfile

@@ -5,3 +5,4 @@ gemspec
 
 gem 'jekyll-feed'
 gem 'jemoji'
+gem 'jekyll-seo-tag'

Gemfile.lock

@@ -60,6 +60,8 @@ GEM
       jekyll (>= 3.7, < 5.0)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
+    jekyll-seo-tag (2.6.1)
+      jekyll (>= 3.3, < 5.0)
     jekyll-target-blank (2.0.0)
       jekyll (>= 3.0, < 5.0)
       nokogiri (~> 1.10)
@@ -127,6 +129,7 @@ PLATFORMS
 DEPENDENCIES
   html-proofer (~> 3.0)
   jekyll-feed
+  jekyll-seo-tag
   jekyll-theme-cayman-blog!
   jemoji
   rubocop (~> 0.50)

_config.yml

@@ -27,6 +27,7 @@ plugins:
   - jekyll-target-blank
   - jekyll-feed
   - jemoji
+  - jekyll-seo-tag
 
 target-blank:
     rel: nofollow

_layouts/default.html

@@ -29,7 +29,7 @@
     <title>{{ page-title }}</title>
 
     {% if site.plugins contains "jekyll-seo-tag" %}
-    <!-- jekyll-seo-tag -->
+        {% seo %}
     {% else %}
     {% include social-metatags.html %}
     {% endif %}