Added Solr partial string match configuration

Steps on how to configure the Solr server to return partial string matches on keyword searches.

docs/webapp/keyword-search/index.rst

@@ -97,3 +97,51 @@ Solr
 See :doc:`/system-requirements/software/solr` for details on how to install Solr.
 
 .. index:: keyword search, quick search, search, Solr, Lucene
+
+Solr Partial String Match Configuration
+---------------------------------------
+In its default configuration, Solr will not match partial search terms. For example a gene named *REVOLUTA* will be 
+returned in the search results for search term "REVOLUTA" but not for search term "REV." In order to have Solr return 
+partial string matches, you must edit its configuration on the Solr server:
+
+1. ADD the following to /var/solr/data/[mine]-search/conf/managed-schema. (This example implements it for hits
+against Gene.primaryIdentifier and Gene.secondaryIdentifier.)
+
+```xml
+<fieldType name="text_ngram" class="solr.TextField" positionIncrementGap="100">
+   <analyzer type="index">
+      <tokenizer class="solr.WhitespaceTokenizerFactory"/>
+      <filter class="solr.NGramFilterFactory" minGramSize="1" maxGramSize="50"/>
+      <filter class="solr.LowerCaseFilterFactory"/>
+   </analyzer>
+   <analyzer type="query">
+      <tokenizer class="solr.WhitespaceTokenizerFactory"/>
+      <filter class="solr.LowerCaseFilterFactory"/>
+   </analyzer>
+</fieldType>
+<field name="gene_primaryidentifier" type="text_ngram" indexed="true" stored="true"/>
+<field name="gene_secondaryidentifier" type="text_ngram" indexed="true" stored="true"/>
+```
+
+2. REMOVE the gene_primaryidentifier and gene_secondaryidentifier field definitions from the earlier part of the file.
+They look like this:
+
+```xml
+<field name="gene_primaryidentifier" type="analyzed_string" multiValued="true" indexed="true" required="false" stored="false"/>
+<field name="gene_secondaryidentifier" type="analyzed_string" multiValued="true" indexed="true" required="false" stored="false"/>
+```
+
+3. RESTART Solr to load the new config, e.g. under System V:
+
+```
+$ systemctl restart solr
+```
+
+4. REBUILD the search index using the Solr-related postprocesses:
+
+```
+./gradlew postprocess -Pprocess=create-search-index 
+```
+
+Your keyword search will now return results on partial matches for the attributes that you configured in 
+Solr (Gene.primaryIdentifier and Gene.secondaryIdentifier in this example).