Add series links

lib/Render/Head.rakumod

@@ -61,6 +61,7 @@ sub site-header(BlogMeta:D $meta) is export {
             header-link 'Index', '/index.html', 'home';
             header-link 'Archive', '/archive.html', 'archive';
             header-link 'Tags', '/tags.html', 'purchase-tag-alt';
+            header-link 'Series', '/series.html', 'book';
             header-link 'About', '/about.html', 'info-circle';
             header-link 'Feed', '/atom.xml', 'rss';
         ];

lib/Render/Post.rakumod

@@ -3,6 +3,7 @@ unit module Render::Post;
 
 use Render::Util;
 use DB::Post;
+use DB::Series;
 
 use HTML::Functional;
 
@@ -81,20 +82,52 @@ sub post-tags(Post:D $post) is export {
     }
 }
 
-sub post-info(Post:D $post) is export {
+sub series-tag(Int:D $post-id, Int:D $series-id, Series:D $series) is export {
+    span :class<post-series-tag>, [
+       a :href("/series/$series-id.html"), [
+          icon 'book';
+          '&nbsp;';
+          span :class<post-series-tag-inner>, [
+              $series.title;
+              '&nbsp;';
+              '(';
+              ($series.post-ids.first($post-id, :k) + 1).Str;
+              '/';
+              $series.post-ids.elems.Str;
+              ')';
+          ]
+       ]
+    ]
+}
+
+sub post-series-tags(Int:D $post-id, Post:D $post, $db) is export {
+    # Find all the series this post is in
+    my @series = $db.series.grep(*.value.contains-post: $post-id);
+    if @series {
+       div :class<post-series-tags>,
+           @series.map(-> $pair {
+               series-tag $post-id, $pair.key, $pair.value
+           });
+    } else {
+        []
+    }
+}
+
+sub post-info(Int:D $id, Post:D $post, $db) is export {
     div :class<post-info>, [
         post-date $post;
         post-edit $post;
         post-read-time $post;
         post-tags $post;
+        post-series-tags $id, $post, $db;
     ];
 }
 
-sub post-header(Post:D $post) is export {
+sub post-header(Int:D $id, Post:D $post, $db) is export {
     header :class<post-header>, [
         div :class<post-title>, [
             h1 $post.title;
         ];
-        post-info $post;
+        post-info $id, $post, $db;
     ]
 }