filter_by_project should be faster

db/migrate/20250722233948_add_index_to_heartbeats_project.rb

@@ -0,0 +1,9 @@
+class AddIndexToHeartbeatsProject < ActiveRecord::Migration[8.0]
+  # this is what i got from stackoverflow
+  disable_ddl_transaction!
+  
+  def change
+    add_index :heartbeats, :project, algorithm: :concurrently
+    add_index :heartbeats, [:project, :time], algorithm: :concurrently
+  end
+end