ruby: add md help file to ierate on

this should be copied/moved into
cocofix/prompt-templates/qhelps
for iterating on LLM-generated fixes

Author: yoff

ruby/ql/src/queries/performance/rb-could-be-async.md

@@ -0,0 +1,46 @@
+# ActiveRecord performance optimisation
+
+## Description
+
+When an AcriveRecord query is executed in a loop, it potentially an n+1 problem.
+This query identifies situations where an ActiveRecord query execution could be pulled out of a loop.
+
+## Recommendation
+Pull the query out of the loop, thus replacing the many calls with a single one.
+
+## Examples
+
+### Suboptimal
+
+The following (suboptimal) example code queries the User object in each iteration of the loop:
+
+```ruby
+repo_names_by_owner.map do |owner_slug, repo_names|
+    owner_id, owner_type = User.where(login: owner_slug).pluck(:id, :type).first
+    owner_type = owner_type == "User" ? "USER" : "ORGANIZATION"
+    rel_conditions = { owner_id: owner_id, name: repo_names }
+
+    nwo_rel = nwo_rel.or(RepositorySecurityCenterConfig.where(rel_conditions)) unless neg
+    nwo_rel = nwo_rel.and(RepositorySecurityCenterConfig.where.not(rel_conditions)) if neg
+  end
+```
+### Fixed
+
+To improve the performance, we instead query the User object once outside the loop, gathereing all necessary information:
+
+```ruby
+# Preload User data
+user_data = User.where(login: repo_names_by_owner.keys).pluck(:login, :id, :type).to_h do |login, id, type|
+    [login, { id: id, type: type == "User" ? "USER" : "ORGANIZATION" }]
+  end
+  
+repo_names_by_owner.each do |owner_slug, repo_names|
+  owner_info = user_data[owner_slug]
+  owner_id = owner_info[:id]
+  owner_type = owner_info[:type]
+  rel_conditions = { owner_id: owner_id, name: repo_names }
+
+  nwo_rel = nwo_rel.or(RepositorySecurityCenterConfig.where(rel_conditions)) unless neg
+  nwo_rel = nwo_rel.and(RepositorySecurityCenterConfig.where.not(rel_conditions)) if neg
+end
+```