Implement state search with new model

app/controllers/api/v1/parks_controller.rb

@@ -5,7 +5,7 @@ module Api::V1
     def index
       parks = Park.all
       if params[:state].present?
-        parks = parks.where("states like '%' || ? || '%'", params[:state])
+        parks = parks.joins(:states).where(parks_by_states: { state: params[:state] })
       end
       render json: {
         total: parks.count,

app/models/park.rb

@@ -1,4 +1,7 @@
 class Park < ApplicationRecord
   has_many :alerts, foreign_key: :park_code, primary_key: :code,
     inverse_of: :park, dependent: :destroy
+  has_many :states, class_name: "ParksByState",
+    foreign_key: :park_code, primary_key: :code,
+    inverse_of: :parks, dependent: :destroy
 end

app/models/parks_by_state.rb

@@ -1,2 +1,4 @@
 class ParksByState < ApplicationRecord
+  has_many :parks, foreign_key: :park_code, primary_key: :code,
+    inverse_of: :states
 end

spec/fixtures/parks_by_states.yml

@@ -0,0 +1,9 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  park_code: crla
+  state: OR
+
+two:
+  park_code: olym
+  state: WA