fix syntax

Author: woodhull

lib/clickhouse-activerecord/schema_dumper.rb

@@ -32,7 +32,7 @@ def tables(stream)
     def table(table, stream)
       if table.match(/^\.inner/).nil?
         sql= ""
-        simple || = ENV['simple'] == 'true'
+        simple ||= ENV['simple'] == 'true'
         unless simple
           stream.puts "  # TABLE: #{table}"
           sql = @connection.show_create_table(table)