https://www.postgresql.org/support/versioning/

- 9.1 EOLed on September 2016.
- 9.2 EOLed on September 2017.

9.3 is also not supported since Nov 8, 2018.  https://www.postgresql.org/about/news/1905/
I think it may be a little bit early to drop PostgreSQL 9.3 yet.

* Deprecated `supports_ranges?` since no other databases support range data type

* Add `supports_materialized_views?` to abstract adapter
Materialized views itself is supported by other databases, other connection adapters may support them

* Remove `with_manual_interventions`
It was only necessary for PostgreSQL 9.1 or earlier

* Drop CI against PostgreSQL 9.2