Allow up to 7 digits for FCA numbers

FCA now has entries listed with up to 7 digits for identification. We
only allowed 6 digits precisely before so this change permits FCA
numbers between 6-7 digits long.

A new run of FCA data will need to run first to backfill the reference
data as prior to this change we were quietly dropping any reference data
identified by FCA numbers not precisely 6 digits long.

app/models/lookup/firm.rb

@@ -3,7 +3,7 @@ class Firm < ApplicationRecord
     has_many :subsidiaries, primary_key: :fca_number, foreign_key: :fca_number
 
     validates :fca_number,
-              length: { is: 6 },
+              length: { in: 6..7 },
               numericality: { only_integer: true }
 
     def subsidiaries?

app/models/lookup/subsidiary.rb

@@ -1,7 +1,7 @@
 module Lookup
   class Subsidiary < ApplicationRecord
     validates :fca_number,
-              length: { is: 6 },
+              length: { in: 6..7 },
               numericality: { only_integer: true }
 
     def self.table_name

app/models/principal.rb

@@ -25,7 +25,7 @@ class Principal < ApplicationRecord
   validates :fca_number,
             presence: true,
             uniqueness: true,
-            length: { is: 6 },
+            length: { in: 6..7 },
             numericality: { only_integer: true }
 
   validates :email_address,

spec/models/lookup/firm_spec.rb

@@ -11,8 +11,9 @@
         expect(described_class.new(fca_number: '123A45')).to_not be_valid
       end
 
-      it 'accepts only 6 digits' do
-        expect(described_class.new(fca_number: 1_234_567)).to_not be_valid
+      it 'accepts between 6 and 7 digits' do
+        expect(described_class.new(fca_number: 1_234_567)).to be_valid
+        expect(described_class.new(fca_number: 1_234_567_8)).to_not be_valid
       end
     end
   end