Fetch adjustments efficiently from Spree::Order

[vl3]

Summary

This commit updates the Spree::Order model to improve the efficiency of fetching adjustments. The approach is to use includes(:adjustments) in the association queries. This tells ActiveRecord to preload the adjustments along with the line items or shipments, resulting in a more efficient single database query for each table.

» o.item_total_before_tax
  Spree::LineItem Load (0.8ms)  SELECT "spree_line_items".* FROM "spree_line_items" WHERE "spree_line_items"."order_id" = $1 ORDER BY "spree_line_items"."created_at" ASC, "spree_line_items"."id" ASC  [["order_id", 8701508]]
  Spree::Adjustment Load (11.7ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746834], ["adjustable_type", "Spree::LineItem"]]
  Spree::Adjustment Load (0.5ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746835], ["adjustable_type", "Spree::LineItem"]]
  Spree::Adjustment Load (0.3ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746836], ["adjustable_type", "Spree::LineItem"]]
  Spree::Adjustment Load (0.3ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746837], ["adjustable_type", "Spree::LineItem"]]
  Spree::Adjustment Load (0.3ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746838], ["adjustable_type", "Spree::LineItem"]]
  Spree::Adjustment Load (0.2ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_id" = $1 AND "spree_adjustments"."adjustable_type" = $2  [["adjustable_id", 43746839], ["adjustable_type", "Spree::LineItem"]]
=> 89.94

» o.item_total_before_tax
  Spree::LineItem Load (0.8ms)  SELECT "spree_line_items".* FROM "spree_line_items" WHERE "spree_line_items"."order_id" = $1 ORDER BY "spree_line_items"."created_at" ASC, "spree_line_items"."id" ASC  [["order_id", 8701508]]
  Spree::Adjustment Load (0.7ms)  SELECT "spree_adjustments".* FROM "spree_adjustments" WHERE "spree_adjustments"."adjustable_type" = $1 AND "spree_adjustments"."adjustable_id" IN ($2, $3, $4, $5, $6, $7)  [["adjustable_type", "Spree::LineItem"], ["adjustable_id", 43746834], ["adjustable_id", 43746835], ["adjustable_id", 43746836], ["adjustable_id", 43746837], ["adjustable_id", 43746838], ["adjustable_id", 43746839]]
=> 89.94

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[kennyadsl]

@vl3 why did you close this?

[vl3]

@kennyadsl there were a few failing tests related, I didn't check them because I had no time at that moment, I will do it soon and reopen!