fix travis links in readme

links were redirects
Making the retrieval of the cache store class a method, also wrote
comments for the expand_cache_key method.
Use new hash syntax in module delegation docs [ci skip]
Fix typo in serialized_attribute_test. [ci skip]
Merge pull request #10368 from demands/fix-typo

Fix typo in serialized_attribute_test. [ci skip]
Merge pull request #10361 from teeparham/patch-1

Fix travis links in readme [ci skip]
Merge pull request #10364 from wangjohn/refactoring_activesupport_cache

Making the retrieval of the cache store class a method
Delegate #unscope query method
StatementInvalid takes WrappedDatabaseException's place
Merge pull request #10372 from jeremy/statement-invalid-wraps-underlying-exception

StatementInvalid takes WrappedDatabaseException's place