Take account of table_name_prefix option.

The Rails option for table_name_prefix and table_name_suffix means they
must be removed when doing a schema dump.

lib/foreigner/schema_dumper.rb

@@ -8,11 +8,11 @@ module SchemaDumper
 
     module ClassMethods
       def dump_foreign_key(foreign_key)
-        statement_parts = [ ('add_foreign_key ' + foreign_key.from_table.inspect) ]
-        statement_parts << foreign_key.to_table.inspect
+        statement_parts = [ ('add_foreign_key ' + remove_prefix_and_suffix(foreign_key.from_table).inspect) ]
+        statement_parts << remove_prefix_and_suffix(foreign_key.to_table).inspect
         statement_parts << (':name => ' + foreign_key.options[:name].inspect)
 
-        if foreign_key.options[:column] != "#{foreign_key.to_table.singularize}_id"
+        if foreign_key.options[:column] != "#{remove_prefix_and_suffix(foreign_key.to_table).singularize}_id"
           statement_parts << (':column => ' + foreign_key.options[:column].inspect)
         end
         if foreign_key.options[:primary_key] != 'id'
@@ -24,6 +24,10 @@ def dump_foreign_key(foreign_key)
 
         statement_parts.join(', ')
       end
+
+      def remove_prefix_and_suffix(table)
+        table.gsub(/^(#{ActiveRecord::Base.table_name_prefix})(.+)(#{ActiveRecord::Base.table_name_suffix})$/,  "\\2")
+      end
     end
 
     def tables_with_foreign_keys(stream)

test/foreigner/schema_dumper_test.rb

@@ -48,6 +48,16 @@ def foreign_keys(table, stream)
     assert_equal ['bar'].to_set, dumper.processed_tables.to_set
   end
 
+  test 'removes table name suffix and prefix' do
+    begin
+      ActiveRecord::Base.table_name_prefix = 'pre_'
+      ActiveRecord::Base.table_name_suffix = '_suf'
+      assert_dump "add_foreign_key \"foos\", \"bars\", :name => \"lulz\"", Foreigner::ConnectionAdapters::ForeignKeyDefinition.new('pre_foos_suf', 'pre_bars_suf', column: 'bar_id', primary_key: 'id', name: 'lulz')
+    ensure
+      ActiveRecord::Base.table_name_suffix = ActiveRecord::Base.table_name_prefix = ''
+    end
+  end
+
   private
     def assert_dump(expected, definition)
       assert_equal expected, MockSchemaDumper.dump_foreign_key(definition)