Add aws based storage configuration documentation

docs/aws_storage.md

+# AWS Storage setup instruction for Loki
+
+## Example config via yaml file
+```yaml
+schema_config:
+  configs:
+  - from: 0
+    store: aws
+    object_store: aws
+    schema: v9
+    index:
+      prefix: dynamodb_table_name
+      period: 0
+storage_config:
+  aws:
+    s3: s3://access_key:secret_access_key@region/bucket_name
+    dynamodbconfig:
+      dynamodb: dynamodb://access_key:secret_access_key@region
+```
+
+## S3 
+
+Loki is using S3 as object storage. It stores log within directories based on
+[`OrgID`](./operations.md#Multi-tenancy). For example, Logs from org `faker'
+will stored in `s3://BUCKET_NAME/faker/`.
+
+The S3 configuration is setup with url format: `s3://access_key:secret_access_key@region/bucket_name`.
+
+## Dynamo DB
+
+Loki uses dynamodb for the index storage. It is used for querying logs, make
+sure you adjuest your throughput to your usage.
+
+DynamoDB access is very similar to S3, however you do not need to specific a
+table name in the storage section.  You will need to set the table name for
+`index.prefix` inside schema config section.
+
+To setup dynamodb, you can do it manually, or use `table_manager` to create and
+maintain the tables for you.  You can find out more info about table manager at
+[cortex
+project](https://github.com/cortexproject/cortex)(https://github.com/cortexproject/cortex). There is an example table manager deployment inside the ksonnet deployment method.  You can find it [here](../production/ksonnet/loki/table-manager.libsonnet)

docs/operations.md

@@ -76,7 +76,11 @@ The chunks are stored under `/tmp/loki/chunks`.
 
 ### Cloud storage
 
+#### Google Cloud Storage
+
 Loki has support for Google Cloud storage.
 Take a look at our [production setup](https://github.com/grafana/loki/blob/a422f394bb4660c98f7d692e16c3cc28747b7abd/production/ksonnet/loki/config.libsonnet#L55) for the relevant configuration fields.
 
-Support for AWS and Azure is also available, but not yet documented.
+
+#### AWS S3 & DynamoDB
+Take a look at our [s3-dynamodb setup](./aws_storage.md)