Remove PostGIS dependency

[scarroll32]

The activerecord-postgis-adapter gem was added with this PR https://github.com/activerecord-hackery/ransack/pull/1541/files#diff-18b0303eda26dc0eb1c3cd5912aa46759501b06e843dedc53c627925a2aa5a5f and detailed in this issue #850

@ldonnet @tindron @dustinagrian can you explain a bit more why we need this? What are the activerecord-postgis-adapter dependency and related CI steps providing?

Does it offer any additional functionality to the Ransack community, or was this included to resolve a specific problem in a project with both ransack and activerecord-postgis-adapter ?

If we are supporting PostGIS, can an entry be added to the documentation?

[scarroll32]

Related rgeo/activerecord-postgis-adapter#183 (comment)

[tindron]

The PostGIS adapter is a superset of the PostgreSQL adapter. Because it identifies itself as PostGIS and not PostgreSQL ransack was not correctly escaping wildcards. The fix was to add PostGIS to the same condition as PostgreSQL so ransack would correctly escape wildcards. The dependency and CI steps were added to validate that ransack continues to function with the PostGIS adapter. There is no additional functionality provided or expected.

[scarroll32]

Great, thank you for explaining that @tindron

I think it would be best to look at how the dependency can be removed at some point. If a way can be found to pass these specs without the PostGIS dependency present, can we remove it?

Is this the original issue in the PostGIS tracker?

[scarroll32]

@tindron see also #1639

If you have any thoughts on this, please let me know.