Fix Template.latest_version Ambiguity Error

[aaronskiba]

Fixes portagenetwork#941 (the same issue exists within DMP Roadmap)

Changes proposed in this PR:

• Prior to this commit, the following error was encountered when applying the search filter within /org_admin/templates:

ActiveRecord::StatementInvalid - PG::AmbiguousColumn: ERROR:  column reference "id" is ambiguous
LINE 1: SELECT COUNT(DISTINCT id) FROM (SELECT MAX(version) AS versi...
                              ^:
  app/views/layouts/_paginable.html.erb:5
  app/controllers/concerns/paginable.rb:82:in `paginable_renderise'
  app/controllers/paginable/templates_controller.rb:25:in `index'

• Tracing the code reveals that the query encountering this error is Template.includes(:org).latest_version.where(customization_of: nil).distinct.total_count.

• Although SELECT "templates.*" is the default behaviour of the .latest_version scope, the ambiguity error is raised unless .select('templates.*') is added explicitly.

[aaronskiba]

Rather than updating the scope itself, I also could've addressed the ambiguity error via the following changes within app/views/layouts/_paginable.html.erb:

However, Template.latest_version seems to be the only scope encountering this error. Also, "SELECT \"templates\".* was still the default behaviour of the scope before these changes were made:

3.1.4 :001 > Template.latest_version.to_sql
Creating scope :publicly_visible. Overwriting existing method Template.publicly_visible.
Creating scope :organisationally_visible. Overwriting existing method Template.organisationally_visible.
 => "SELECT \"templates\".* FROM (SELECT MAX(version) AS version, \"templates\".\"family_id\" FROM \"templates\" WHERE \"templates\".\"archived\" = FALSE GROUP BY \"templates\".\"family_id\") current INNER JOIN templates ON current.version = templates.version\n  AND current.family_id = templates.family_id\nINNER JOIN orgs ON orgs.id = templates.org_id WHERE \"templates\".\"archived\" = FALSE"