Fix typo in IndexerService.md

docs/tutorial/IndexerService.md

@@ -251,7 +251,7 @@ API will respond with status of task.
 
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-##Shema Service adoption <a name="schema-service-adoption"></a>
+##Schema Service adoption <a name="schema-service-adoption"></a>
 
 Indexer service is in adaptation process to use schemas from the Schema service instead of Storage Service.
 The Indexer Service retrieves a schema from the Schema Service if the schema is not found on the Storage Service.