added index type parameter to ensureIndex

- required to create geo index for geoNear test

Author: mtrezza

src/Adapters/Storage/Mongo/MongoStorageAdapter.js

@@ -682,15 +682,16 @@ export class MongoStorageAdapter implements StorageAdapter {
     schema: SchemaType,
     fieldNames: string[],
     indexName: ?string,
-    caseInsensitive: boolean = false
+    caseInsensitive: boolean = false,
+    indexType: any = 1
   ): Promise<any> {
     schema = convertParseSchemaToMongoSchema(schema);
     const indexCreationRequest = {};
     const mongoFieldNames = fieldNames.map(fieldName =>
       transformKey(className, fieldName, schema)
     );
     mongoFieldNames.forEach(fieldName => {
-      indexCreationRequest[fieldName] = 1;
+      indexCreationRequest[fieldName] = indexType;
     });
 
     const defaultOptions: Object = { background: true, sparse: true };

src/Adapters/Storage/StorageAdapter.js

@@ -92,7 +92,8 @@ export interface StorageAdapter {
     schema: SchemaType,
     fieldNames: string[],
     indexName?: string,
-    caseSensitive?: boolean
+    caseSensitive?: boolean,
+    indexType?: any
   ): Promise<any>;
   ensureUniqueness(
     className: string,