Adds session creation code in Auth.js (#4574)

src/Controllers/DatabaseController.js

@@ -511,7 +511,7 @@ class DatabaseController {
   addRelation(key: string, fromClassName: string, fromId: string, toId: string) {
     const doc = {
       relatedId: toId,
-      owningId : fromId
+      owningId: fromId
     };
     return this.adapter.upsertOneObject(`_Join:${key}:${fromClassName}`, relationSchema, doc, doc);
   }
@@ -658,7 +658,7 @@ class DatabaseController {
 
   // Returns a promise for a list of owning ids given some related ids.
   // className here is the owning className.
-  owningIds(className: string, key: string, relatedIds: string): Promise<string[]> {
+  owningIds(className: string, key: string, relatedIds: string[]): Promise<string[]> {
     return this.adapter.find(joinTableName(className, key), relationSchema, { relatedId: { '$in': relatedIds } }, {})
       .then(results => results.map(result => result.owningId));
   }