Full text support in peewee

Adds support for full text search in peewee with the creation of two new field types: `FullIndexedCharField` and `FullIndexedTextField`.

Note that this change depends upon https://github.com/zzzeek/sqlalchemy/pull/339

[Delivers #137453279]
[Delivers #137453317]

data/model/sqlalchemybridge.py

@@ -1,5 +1,5 @@
 from sqlalchemy import (Table, MetaData, Column, ForeignKey, Integer, String, Boolean, Text,
-                        DateTime, Date, BigInteger, Index)
+                        DateTime, Date, BigInteger, Index, text)
 from peewee import (PrimaryKeyField, CharField, BooleanField, DateTimeField, TextField,
                     ForeignKeyField, BigIntegerField, IntegerField, DateField)
 
@@ -28,6 +28,7 @@ def gen_sqlalchemy_metadata(peewee_model_list):
     meta = model._meta
 
     all_indexes = set(meta.indexes)
+    fulltext_indexes = []
 
     columns = []
     for field in meta.sorted_fields:
@@ -60,6 +61,10 @@ def gen_sqlalchemy_metadata(peewee_model_list):
       else:
         raise RuntimeError('Unknown column type: %s' % field)
 
+      if hasattr(field, '__fulltext__'):
+        # Add the fulltext index for the field, based on whether we are under MySQL or Postgres.
+        fulltext_indexes.append(field.name)
+
       for option_name in OPTIONS_TO_COPY:
         alchemy_option_name = (OPTION_TRANSLATIONS[option_name]
                                if option_name in OPTION_TRANSLATIONS else option_name)
@@ -81,4 +86,11 @@ def gen_sqlalchemy_metadata(peewee_model_list):
       col_refs = [getattr(new_table.c, col_name) for col_name in col_names]
       Index(index_name, *col_refs, unique=unique)
 
+    for col_field_name in fulltext_indexes:
+      index_name = '%s_%s__fulltext' % (meta.db_table, col_field_name)
+      col_ref = getattr(new_table.c, col_field_name)
+      Index(index_name, col_ref, postgresql_ops={col_field_name: 'gin_trgm_ops'},
+                                 postgresql_using='gin',
+                                 mysql_prefix='FULLTEXT')
+
   return metadata