diff --git a/blog b/blog
index b6b183d..81c14b0 100755
--- a/blog
+++ b/blog
@@ -21,17 +21,23 @@ sub load-db(IO::Path $file --> DB::PostDB:D) {
     }
 }
 
+#| Write the databse to the provided file
+sub write-db(IO::Path $file, DB::PostDB $db) {
+    my $output = $db.to-json;
+    $file.spurt: $output;
+}
+
 #| Initalize the database
 multi MAIN(
     "db",
     "init",
     #| The path of the database file
-    IO::Path :$file = $blog-dir.add("db.json"),
+    IO::Path(Str) :$db-file = $blog-dir.add("db.json"),
     #| Overwrite an already existing database file
     Bool :$force
 ) {
-    die "Database file already exists, use --force to overwrite: {$file.Str}"
-    if $file.e && !$force;
+    die "Database file already exists, use --force to overwrite: {$db-file.Str}"
+    if $db-file.e && !$force;
 
     print "Blog Title: ";
     my $title = get;
@@ -43,9 +49,9 @@ multi MAIN(
     my $db = DB::PostDB.new: meta => $meta;
 
     if $force {
-        $file.spurt: $db.to-json, :create-only;
+        $db-file.spurt: $db.to-json, :create-only;
     } else {
-        $file.spurt: $db.to-json;
+        $db-file.spurt: $db.to-json;
     }
 }
 
@@ -54,8 +60,34 @@ multi MAIN(
     "db",
     "verify",
     #| The path of the database file
-    IO::Path :$file = $blog-dir.add("db.json"),
+    IO::Path(Str) :$db = $blog-dir.add("db.json"),
 ) {
-    load-db $file;
+    load-db $db;
     say "Database OK";
 }
+
+#| Create a new markdown post
+
+multi MAIN(
+    "new",
+    "markdown",
+    #| The path to the markdown file
+    IO::Path(Str) $source,
+    #| The path of the database file
+    IO::Path(Str) :$db-file = $blog-dir.add("db.json"),
+    #| The date/time the post should be recorded as posted at
+    DateTime(Str) :$posted-at = DateTime.now,
+    #| Should the post be hidden from the archive?
+    Bool :$hidden = False,
+) {
+    my $db = load-db $db-file;
+    my $id =
+        $db.insert-post:
+        DB::MarkdownPost.new(
+            source => $source.absolute.IO,
+            posted-at => $posted-at,
+            hidden => $hidden,
+        );
+    write-db $db-file, $db;
+    say 'Post inserted with id ', $id;
+}
diff --git a/lib/DB.rakumod b/lib/DB.rakumod
index a242fce..9d3f5dc 100644
--- a/lib/DB.rakumod
+++ b/lib/DB.rakumod
@@ -17,15 +17,37 @@ class BlogMeta is json(:pretty) {
 #| Shared post meta-data
 role Post is json {
     #| The location of the source file for the post
-    has IO::Path:D $.source is required;
+    has
+    IO::Path:D $.source
+               is required
+               is json(
+        :to-json(*.Str),
+        :from-json(*.IO)
+    );
     #| The time to display for the creation of the post
-    has DateTime:D $.posted-at is required;
+    has
+    DateTime:D $.posted-at
+               is required
+               is json(
+        :to-json(*.Str),
+        :from-json(*.DateTime)
+    );
     #| An optional list of edit times for the post
-    has DateTime:D @.edited-at = [];
+    has
+    DateTime:D @.edited-at
+               is json(
+        :to-json(
+            value => { $^value.Str }
+        ),
+        :from-json(
+            value => { $^value.DateTime }
+        )
+    )
+    = [];
     #| An optional list of extra slugs to use for this post
-    has Str:D @.slugs = [];
+    has Str:D @.slugs is json = [];
     #| Should the post be hidden from the main list
-    has Bool:D $.hidden is rw = False;
+    has Bool:D $.hidden is json is rw = False;
 
     #| Get the title for this post, intended to be extracted from whatever
     #| document produced it
@@ -37,6 +59,7 @@ role Post is json {
         my $long-title-slug = self.title.lc.subst: /\h*/, '-';
         return [$long-title-slug, @!slugs].flat.Array;
     }
+
 }
 
 #| A plain markdown post
@@ -63,5 +86,21 @@ class PostDB is json(:pretty) {
    #| The metadat for the blog
    has BlogMeta:D $.meta is required;
    #| A mapping from post ids to posts
-   has Hash[Int:D, Post:D] %.posts = %();
+   has %.posts{Int:D} of MarkdownPost:D = %();
+
+   #| Get the next unused post ID
+   method next-post-id(--> Int) {
+       if %!posts {
+           %!posts.keys.max + 1
+       } else {
+           0
+       }
+   }
+
+   #| Insert a new post to the DB, returning its id
+   method insert-post(Post:D $post --> Int) {
+       my $id = self.next-post-id;
+       %!posts{$id} = $post;
+       $id
+   }
 }