Add endpoint for plugin subscription

src/plugin/subscriptions.cr

@@ -75,7 +75,7 @@ struct SubscriptionList
   forward_missing_to @ary
 
   def initialize(@dir)
-    @path = Path[@dir, "subscriptions.json"]
+    @path = Path[@dir, "subscriptions.json"].to_s
     if File.exists? @path
       @ary = Array(Subscription).from_json File.read @path
     end

src/routes/api.cr

@@ -630,6 +630,30 @@ struct APIRouter
       end
     end
 
+    post "/api/admin/plugin/subscribe" do |env|
+      begin
+        plugin_id = env.params.json["plugin"].as String
+        filters = Array(Filter).from_json env.params.json["filters"].to_s
+        name = env.params.json["name"].as String
+
+        sub = Subscription.new plugin_id, name
+        sub.filters = filters
+
+        plugin = Plugin.new plugin_id
+        plugin.subscribe sub
+
+        send_json env, {
+          "success" => true,
+        }.to_json
+      rescue e
+        Logger.error e
+        send_json env, {
+          "success" => false,
+          "error"   => e.message,
+        }.to_json
+      end
+    end
+
     Koa.describe "Lists the chapters in a title from a plugin"
     Koa.tags ["admin", "downloader"]
     Koa.query "plugin", schema: String