Specify the subset when creating a build job

ofborg/src/message/buildjob.rs

@@ -8,7 +8,14 @@ use amqp::protocol;
 pub struct BuildJob {
     pub repo: Repo,
     pub pr: Pr,
-    pub attrs: Vec<String>
+    pub subset: Option<Subset>,
+    pub attrs: Vec<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+pub enum Subset {
+    Nixpkgs,
+    NixOS,
 }
 
 pub fn from(data: &Vec<u8>) -> Result<BuildJob, serde_json::error::Error> {

ofborg/src/tasks/githubcommentfilter.rs

@@ -99,7 +99,8 @@ impl worker::SimpleWorker for GitHubCommentWorker {
                                 head_sha: pr.head.sha.clone(),
                                 target_branch: Some(pr.base.commit_ref.clone())
                             },
-                            attrs: attrs
+                            subset: Some(buildjob::Subset::Nixpkgs),
+                            attrs: attrs,
                         };
 
                         let props = BasicProperties {