Expand methods checked for SQLi significantly

include methods on #connection and delete_all/destroy_all
Fixes #434
Merge pull request #438 from presidentbeef/check_db_connection_for_sqli

Expand methods checked for SQLi significantly
Also catch #connection calls on ActiveRecord::Base
Merge pull request #439 from presidentbeef/active_record_base_connect_sqli

Also catch #connection calls on ActiveRecord::Base
Merge branch 'master' into support_lts_versions

Conflicts:
	lib/brakeman/checks/check_sql.rb
Fix Rails LTS detection