Fix #282 with error "foreign_keys is not implemented"

Author: ctran

lib/annotate/annotate_models.rb

@@ -288,7 +288,9 @@ def get_foreign_key_info(klass, options={})
  fk_info = "#\n# Foreign Keys\n#\n"
  end
 
- foreign_keys = klass.connection.respond_to?(:foreign_keys) ? klass.connection.foreign_keys(klass.table_name) : []
+ return "" unless klass.connection.supports_foreign_keys? && klass.connection.respond_to?(:foreign_keys)
+
+ foreign_keys = klass.connection.foreign_keys(klass.table_name)
  return "" if foreign_keys.empty?
 
  max_size = foreign_keys.collect{|fk| fk.name.size}.max + 1