Add places to list of filters and aggregations

** Why are these changes being introduced:

* The TIMDEX API has added support for a Places filter and aggregation,
  so the UI should be extended to take advantage of this.

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/post-128

** How does this address that need:

* This builds on the work from #128 and #131, to include the Places
  feature in our displayed filters and aggregations.

** Document any side effects to this change:

* These changes will require that our test cassettes are re-generated,
  which will happen in the next commit.

README.md

@@ -57,6 +57,7 @@ change as part of the work.
 - `FILTER_FORMAT`: The name to use instead of "Format" for that filter / aggregation.
 - `FILTER_LANGUAGE`: The name to use instead of "Language" for that filter / aggregation.
 - `FILTER_LITERARY_FORM`: The name to use instead of "Literary form" for that filter / aggregation.
+- `FILTER_PLACE`: The name to use instead of "Place" for that filter / aggregation.
 - `FILTER_SOURCE`: The name to use instead of "Source" for that filter / aggregation.
 - `FILTER_SUBJECT`: The name to use instead of "Subject" for that filter / aggregation.
 - `GDT`: Enables features related to geospatial data discovery. Setting this variable with any value will trigger GDT

app/helpers/filter_helper.rb

@@ -26,6 +26,7 @@ def nice_labels
       formatFilter: ENV.fetch('FILTER_FORMAT', 'Format'),
       languagesFilter: ENV.fetch('FILTER_LANGUAGE', 'Language'),
       literaryFormFilter: ENV.fetch('FILTER_LITERARY_FORM', 'Literary form'),
+      placesFilter: ENV.fetch('FILTER_PLACE', 'Place'),
       sourceFilter: ENV.fetch('FILTER_SOURCE', 'Source'),
       subjectsFilter: ENV.fetch('FILTER_SUBJECT', 'Subject')
     }

app/models/enhancer.rb

@@ -2,8 +2,8 @@ class Enhancer
   attr_accessor :enhanced_query
 
   QUERY_PARAMS = %i[q citation contentType contributors fundingInformation identifiers locations subjects title].freeze
-  FILTER_PARAMS = %i[contentTypeFilter contributorsFilter formatFilter languagesFilter literaryFormFilter sourceFilter
-                     subjectsFilter].freeze
+  FILTER_PARAMS = %i[contentTypeFilter contributorsFilter formatFilter languagesFilter literaryFormFilter placesFilter
+                     sourceFilter subjectsFilter].freeze
 
   # accepts all params as each enhancer may require different data
   def initialize(params)

app/models/query_builder.rb

@@ -3,8 +3,8 @@ class QueryBuilder
 
   RESULTS_PER_PAGE = 20
   QUERY_PARAMS = %w[q citation contributors fundingInformation identifiers locations subjects title].freeze
-  FILTER_PARAMS = %i[contentTypeFilter contributorsFilter formatFilter languagesFilter literaryFormFilter sourceFilter
-                     subjectsFilter].freeze
+  FILTER_PARAMS = %i[contentTypeFilter contributorsFilter formatFilter languagesFilter literaryFormFilter placesFilter
+                     sourceFilter subjectsFilter].freeze
 
   def initialize(enhanced_query)
     @query = {}

app/models/timdex_search.rb

@@ -19,6 +19,7 @@ class TimdexSearch < TimdexBase
       $formatFilter: [String!]
       $languagesFilter: [String!]
       $literaryFormFilter: String
+      $placesFilter: [String!]
       $sourceFilter: [String!]
       $subjectsFilter: [String!]
     ) {
@@ -38,6 +39,7 @@ class TimdexSearch < TimdexBase
         formatFilter: $formatFilter
         languagesFilter: $languagesFilter
         literaryFormFilter: $literaryFormFilter
+        placesFilter: $placesFilter
         sourceFilter: $sourceFilter
         subjectsFilter: $subjectsFilter
       ) {
@@ -86,6 +88,10 @@ class TimdexSearch < TimdexBase
             key
             docCount
           }
+          places {
+            key
+            docCount
+          }
           source {
             key
             docCount