Add documentation for write CSV.

Author: jhorbulyk

README.md

@@ -2,36 +2,83 @@
 
 > A CSV component for the [elastic.io platform](http://www.elastic.io "elastic.io platform").
 
-This is an open source component to work with [CSV](http://en.wikipedia.org/wiki/Comma-separated_values) files in your integration flow and is developed specifically to run on [elastic.io platform](http://www.elastic.io "elastic.io platform"). You can clone it and change it as you wish. However, **if you plan to deploy it into [elastic.io platform](http://www.elastic.io "elastic.io platform") you must follow sets of instructions to succeed**.
+This is an open source component to work with
+[CSV](http://en.wikipedia.org/wiki/Comma-separated_values) files in your
+integration flow and is developed specifically to run on [elastic.io
+platform](http://www.elastic.io "elastic.io platform"). You can clone it and
+change it as you wish. However, **if you plan to deploy it into [elastic.io
+platform](http://www.elastic.io "elastic.io platform") you must follow sets of
+instructions to succeed**.
 
-> **PLEASE NOTE:** This is a working component for **CSV** files, however, it may not be suitable for every use case. Not all functionalities are included in this component template. **It is your responsibility to add and modify this component to suit your integration needs.**
+> **PLEASE NOTE:** This is a working component for **CSV** files, however, it
+may not be suitable for every use case. Not all functionality is included in
+this component template. **It is your responsibility to add and modify this
+component to suit your integration needs.**
 
 ## Before you Begin
 
-Before you can deploy any code into our system **you must be a registered elastic.io platform user**. Please see our home page at [http://www.elastic.io](http://www.elastic.io) to learn how.
+Before you can deploy any code into our system **you must be a registered
+elastic.io platform user**. Please see our home page at
+[http://www.elastic.io](http://www.elastic.io) to learn how.
 
 > Any attempt to deploy a code into our platform without a registration would fail.
 
-After the registration and opening of the account you must **[upload your SSH Key](http://docs.elastic.io/docs/ssh-key)** into our platform.
+After the registration and opening of the account you must **[upload your SSH
+Key](http://docs.elastic.io/docs/ssh-key)** into our platform.
 
-> If you fail to upload you SSH Key you will get **permission denied** error during the deployment.
+> If you fail to upload you SSH Key you will get **permission denied** error
+during the deployment.
 
 ## Getting Started
 
-After registration and uploading of your SSH Key you can proceed to deploy it into our system. At this stage we suggest you to:
-* [Create a team](http://docs.elastic.io/page/team-management) to work on your new component. This is not required but will be automatically created using random naming by our system so we suggest you name your team accordingly.
-* [Create a repository](http://docs.elastic.io/page/repository-management) where your new component is going to *reside* inside the team that you have just created. For a simplicity you can name your repository **csv-component** or **csv**.
+After registration and uploading of your SSH Key you can proceed to deploy it
+into our system. At this stage we suggest you to:
+* [Create a team](http://docs.elastic.io/page/team-management) to work on your
+ new component. This is not required but will be automatically created using
+ random naming by our system so we suggest you name your team accordingly.
+* [Create a repository](http://docs.elastic.io/page/repository-management) where
+* your new component is going to *reside* inside the team that you have just
+* created. For a simplicity you can name your repository **csv-component** or
+* **csv**.
 
 ```bash
 $ git clone https://github.com/elasticio/csv-component.git csv-component
 
 $ cd csv-component
 ```
-Now you can edit your version of **csv-component** component and change according to your needs - that is if you know what you are doing. Or you can just ``PUSH``it into our system to see the process in action:
+Now you can edit your version of **csv-component** component and change
+according to your needs - that is if you know what you are doing. Or you can
+just ``PUSH``it into our system to see the process in action:
 
 ```bash
 $ git remote add elasticio [email protected]:csv-component.git
 
 $ git push elasticio master
 ```
-Obviously the naming of your team and repository is entirely up-to you and if you do not put any corresponding naming our system will auto generate it for you but the naming might not entirely correspond to your project requirements.
+Obviously the naming of your team and repository is entirely up-to you and if
+you do not put any corresponding naming our system will auto generate it for you
+but the naming might not entirely correspond to your project requirements.
+
+## Write CSV attachment
+
+Multiple incoming events can be combined into one CSV file with the write CSV
+action.  Incoming events will be written into the CSV file until there is a gap
+of more than 10 seconds between events.  As part of the component setup, one
+must specify the columns of the CSV file.  These columns will be published as
+the header in the first row.  For each incoming event, the value for each header
+will be stringified and written as the value for that cell.  All other
+properties will be ignored.  For example, headers ``foo,bar`` along with the
+following JSON events
+
+    {"foo":"myfoo", "bar":"mybar"}
+    {"foo":"myfoo", "bar":[1,2]}
+    {"bar":"mybar", "baz":"mybaz"}
+
+will produce the following ``.csv`` file:
+
+    foo,bar
+    myfoo,mybar
+    myfoo,"[1,2]"
+    ,mybar
+
+Currently no formatting is performed as part of CSV Write.