Update seed-fu to a version compatible with postgresql 10

Gemfile

@@ -115,7 +115,7 @@ gem 'google-api-client', '~> 0.13.6'
 gem 'unf', '~> 0.1.4'
 
 # Seed data
-gem 'seed-fu', '2.3.6' # Upgrade to > 2.3.7 once https://github.com/mbleigh/seed-fu/issues/123 is solved
+gem 'seed-fu', '~> 2.3.7'
 
 # Markdown and HTML processing
 gem 'html-pipeline', '~> 1.11.0'

Gemfile.lock

@@ -831,7 +831,7 @@ GEM
       rake (>= 0.9, < 13)
       sass (~> 3.5.3)
     securecompare (1.0.0)
-    seed-fu (2.3.6)
+    seed-fu (2.3.7)
       activerecord (>= 3.1)
       activesupport (>= 3.1)
     select2-rails (3.5.9.3)
@@ -1170,7 +1170,7 @@ DEPENDENCIES
   sanitize (~> 2.0)
   sass-rails (~> 5.0.6)
   scss_lint (~> 0.56.0)
-  seed-fu (= 2.3.6)
+  seed-fu (~> 2.3.7)
   select2-rails (~> 3.5.9)
   selenium-webdriver (~> 3.5)
   sentry-raven (~> 2.5.3)

config/initializers/ar5_pg_10_support.rb

@@ -1,5 +1,6 @@
 raise "Vendored ActiveRecord 5 code! Delete #{__FILE__}!" if ActiveRecord::VERSION::MAJOR >= 5
 
+require 'active_record/connection_adapters/postgresql_adapter'
 require 'active_record/connection_adapters/postgresql/schema_statements'
 
 #
@@ -10,6 +11,14 @@ require 'active_record/connection_adapters/postgresql/schema_statements'
 # rubocop:disable all
 module ActiveRecord
   module ConnectionAdapters
+
+    # We need #postgresql_version to be public as in ActiveRecord 5 for seed_fu
+    # to work. In ActiveRecord 4, it is protected.
+    # https://github.com/mbleigh/seed-fu/issues/123
+    class PostgreSQLAdapter
+      public :postgresql_version
+    end
+
     module PostgreSQL
       module SchemaStatements
         # Resets the sequence of a table's primary key to the maximum value.