Add missing unique index to geo_node_group_links table

db/migrate/20170717213940_create_geo_node_group_links.rb

@@ -8,17 +8,23 @@ class CreateGeoNodeGroupLinks < ActiveRecord::Migration
   def up
     create_table :geo_node_group_links do |t|
       t.references :geo_node, index: true, foreign_key: { on_delete: :cascade }, null: false
-      t.integer :group_id, index: true, null: false
+      t.integer :group_id, null: false
     end
 
     add_timestamps_with_timezone :geo_node_group_links
 
     add_concurrent_foreign_key :geo_node_group_links, :namespaces, column: :group_id, on_delete: :cascade
+
+    add_concurrent_index :geo_node_group_links, [:geo_node_id, :group_id], unique: true
   end
 
   def down
     remove_foreign_key :geo_node_group_links, column: :group_id
 
+    if index_exists?(:geo_node_group_links, [:geo_node_id, :group_id])
+      remove_concurrent_index :geo_node_group_links, [:geo_node_id, :group_id]
+    end
+
     drop_table :geo_node_group_links
   end
 end

db/schema.rb

@@ -640,8 +640,8 @@ ActiveRecord::Schema.define(version: 20170803130232) do
     t.datetime "updated_at", null: false
   end
 
+  add_index "geo_node_group_links", ["geo_node_id", "group_id"], name: "index_geo_node_group_links_on_geo_node_id_and_group_id", unique: true, using: :btree
   add_index "geo_node_group_links", ["geo_node_id"], name: "index_geo_node_group_links_on_geo_node_id", using: :btree
-  add_index "geo_node_group_links", ["group_id"], name: "index_geo_node_group_links_on_group_id", using: :btree
 
   create_table "geo_nodes", force: :cascade do |t|
     t.string "schema"
@@ -1985,7 +1985,7 @@ ActiveRecord::Schema.define(version: 20170803130232) do
   add_foreign_key "geo_event_log", "geo_repository_renamed_events", column: "repository_renamed_event_id", name: "fk_86c84214ec", on_delete: :cascade
   add_foreign_key "geo_event_log", "geo_repository_updated_events", column: "repository_updated_event_id", on_delete: :cascade
   add_foreign_key "geo_node_group_links", "geo_nodes", on_delete: :cascade
-  add_foreign_key "geo_node_group_links", "namespaces", column: "group_id", on_delete: :cascade
+  add_foreign_key "geo_node_group_links", "namespaces", column: "group_id", name: "fk_e684c3550a", on_delete: :cascade
   add_foreign_key "geo_repository_renamed_events", "projects", on_delete: :cascade
   add_foreign_key "geo_repository_updated_events", "projects", on_delete: :cascade
   add_foreign_key "index_statuses", "projects", name: "fk_74b2492545", on_delete: :cascade