Small tidy ups to local authority models

This makes a couple of minor changes to the local authority related
models to tidy up the code.

Author: thomasleese

app/models/local_authority.rb

@@ -25,17 +25,15 @@
 #  index_local_authorities_on_nation_and_short_name  (nation,short_name)
 #  index_local_authorities_on_short_name             (short_name)
 #
+
 class LocalAuthority < ApplicationRecord
   self.primary_key = :mhclg_code
 
   validates :mhclg_code, uniqueness: true
   validates :gias_code, uniqueness: true, allow_nil: true
   validates :gss_code, uniqueness: true, allow_nil: true
 
-  has_many :postcodes,
-           foreign_key: :gss_code,
-           primary_key: :gss_code,
-           class_name: "LocalAuthority::Postcode"
+  has_many :postcodes, foreign_key: :gss_code, primary_key: :gss_code
 
   enum :nation,
        {
@@ -80,8 +78,6 @@ def self.from_my_society_import_row(data)
   end
 
   def self.for_postcode(postcode)
-    joins(:postcodes).merge(
-      LocalAuthority::Postcode.where(value: postcode)
-    ).first
+    joins(:postcodes).merge(Postcode.where(value: postcode)).first
   end
 end

app/models/local_authority/postcode.rb

@@ -14,11 +14,9 @@
 #  index_local_authority_postcodes_on_gss_code  (gss_code)
 #  index_local_authority_postcodes_on_value     (value) UNIQUE
 #
+
 class LocalAuthority::Postcode < ApplicationRecord
-  belongs_to :local_authority,
-             foreign_key: :gss_code,
-             primary_key: :gss_code,
-             optional: true
+  belongs_to :local_authority, foreign_key: :gss_code, primary_key: :gss_code
 
   normalizes :value,
              with: ->(given_value) do

app/models/location.rb

@@ -31,6 +31,7 @@
 #  index_locations_on_urn             (urn) UNIQUE WHERE ((type = 0) AND (site IS NULL))
 #  index_locations_on_urn_and_site    (urn,site) UNIQUE
 #
+
 class Location < ApplicationRecord
   self.inheritance_column = nil