Adding a HowTo Guide (#44)

Author: sanathkr

HOWTO.md

@@ -0,0 +1,83 @@
+# How to create serverless applications using AWS SAM
+AWS Serverless Application Model (AWS SAM) allows you to easily create and 
+manage resources used in your serverless application using AWS CloudFormation. 
+You can define your serverless application as a SAM template - a JSON or YAML 
+configuration file that describes Lambda function, API endpoints and
+other resources in your application. Using nifty commands, you upload this 
+template to CloudFormation which creates all the individual resources and
+groups them into a *CloudFormation Stack* for ease of management. 
+When you update your SAM template, you will re-deploy the changes to 
+this stack. AWS CloudFormation will take care of updating the individual
+resources for you.
+
+
+The remainder of document explains how to write SAM templates and 
+deploy them via AWS CloudFormation. 
+
+## Writing SAM Template
+Checkout the [latest specification](versions/2016-10-31.md) for details on how to write a SAM template
+
+## Packing Artifacts
+Before you can deploy a SAM template, you should first upload your Lambda 
+function code zip and API's OpenAPI File to S3. Set the `CodeUri` and 
+`DefinitionUri` properties to the S3 URI of uploaded files. You
+can choose to do this manually or use `aws cloudformation package` [CLI command](http://docs.aws.amazon.com/cli/latest/reference/cloudformation/package.html) to automate the task of uploading local artifacts to S3 bucket. The command returns a copy of your template, replacing references to local artifacts with S3 location where the command uploaded your artifacts. 
+
+To use this command, set `CodeUri` property to be the path to your 
+source code folder/zip/jar and `DefinitionUri` property to be a path to 
+your OpenAPI file, as shown in the example below 
+
+```
+MyLambdaFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+        CodeUri: ./code
+        ...
+
+MyApi:
+    Type: AWS::Serverless::Api
+    Properties:
+        DefinitionUri: ./specs/swagger.yaml
+        ...
+```
+
+Run the following command to upload your artifacts to S3 and output a 
+packaged template that can be readily deployed to CloudFormation.
+```
+aws cloudformation package \
+    --template-file /path_to_template/template.yaml \
+    --s3-bucket bucket-name \
+    --output-template-file packaged-template.yaml
+```
+
+The packaged template will look something like this:
+```
+MyLambdaFunction:
+    Type: AWS::Serverless::Function
+    Properties:
+        CodeUri: s3://<mybucket>/<my-zipfile-path>
+        ...
+
+MyApi:
+    Type: AWS::Serverless::Api
+    Properties:
+        DefinitionUri: s3://<mybucket>/<my-openapi-file-path>
+        ...
+```
+
+
+## Deploying to AWS CloudFormation
+SAM template is deployed to AWS CloudFormation by [creating a changeset](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-changesets-create.html)
+using the SAM template followed by [executing the changeset](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-changesets-execute.html). 
+Think of a ChangeSet as a diff between your current stack template and the new template that you are deploying. After you create a ChangeSet, you have the opportunity to examine the diff before executing it. Both the AWS Console and AWS CLI provide commands to create and execute a changeset. 
+
+Alternatively, you can use `aws cloudformation deploy` CLI command to deploy the SAM template. Under-the-hood it creates and executes a changeset and waits until the deployment completes. It also prints debugging hints when the deployment fails. Run the following command to deploy the packaged template to a stack called `my-new-stack`:
+
+```
+aws cloudformation deploy \
+    --template-file /path_to_template/packaged-template.yaml \
+    --stack-name my-new-stack \
+    --capabilities CAPABILITY_IAM
+```
+
+Refer to the [documentation](http://docs.aws.amazon.com/cli/latest/reference/cloudformation/deploy/index.html) for more details.

README.md

@@ -18,3 +18,8 @@ version.
 
 Each section should contain folders named per version to avoid confusion between
 the versions.
+
+## Usage and Examples
+Checkout the [How-To Guide](HOWTO.md) and [examples folder](examples/) for 
+detailed instructions on how to write AWS SAM templates and deploy them 
+to AWS CloudFormation