unique: true on cluster_id index on cert_manager

db/migrate/20181101191341_create_clusters_applications_cert_manager.rb

@@ -7,12 +7,13 @@ class CreateClustersApplicationsCertManager < ActiveRecord::Migration
 
   def change
     create_table :clusters_applications_cert_managers do |t|
-      t.references :cluster, null: false, unique: true, index: true, foreign_key: { on_delete: :cascade }
+      t.references :cluster, null: false, unique: true, index: false, foreign_key: { on_delete: :cascade }
       t.integer :status, null: false
       t.string :version, null: false
       t.string :email, null: false
       t.timestamps_with_timezone null: false
       t.text :status_reason
+      t.index :cluster_id, unique: true
     end
   end
 end

db/schema.rb

@@ -648,7 +648,7 @@ ActiveRecord::Schema.define(version: 20181112103239) do
     t.datetime_with_timezone "created_at", null: false
     t.datetime_with_timezone "updated_at", null: false
     t.text "status_reason"
-    t.index ["cluster_id"], name: "index_clusters_applications_cert_managers_on_cluster_id", using: :btree
+    t.index ["cluster_id"], name: "index_clusters_applications_cert_managers_on_cluster_id", unique: true, using: :btree
   end
 
   create_table "clusters_applications_helm", force: :cascade do |t|