add course-specific user information

app.rb

@@ -285,7 +285,7 @@ post "#{api_prefix}/users" do
 end
 
 get "#{api_prefix}/users/:user_id" do |user_id|
-  user.to_hash(complete: bool_complete).to_json
+  user.to_hash(complete: bool_complete, course_id: params["course_id"]).to_json
 end
 
 put "#{api_prefix}/users/:user_id" do |user_id|

models/user.rb

@@ -64,6 +64,11 @@ class User
                         "upvoted_ids" => upvoted_ids,
                         "downvoted_ids" => downvoted_ids)
     end
+    if params[:course_id]
+      hash = hash.merge("threads_count" => comment_threads.where(course_id: params[:course_id]).count,
+                        "comments_count" => comments.where(course_id: params[:course_id]).count,
+                       )
+    end
     hash
   end