Feature: Add Slack Archiver application idea

Add Slack Archiver application idea
- Note that this is an advanced application. Although the requirements are small
there are a number of complex implementation details.
- This application will also require considerable design.

Resolves: N/a
See also: N/a

Projects/Slack-Archiver.md

@@ -0,0 +1,48 @@
+# Application Name
+
+Slack is a tool many teams rely on for collaboration not only between
+developers, but also between developers and their users. It's especially
+attractive to Open Source Software (OSS) teams since it supports a highly
+functional free tier.
+
+One problem is the free tier is limited to a maximum of 10K messages. When
+this limit is reached older messages become unavailable since they are 
+purged. This is very impactful to active Slack teams and communities since
+older messages quite often hold a great deal of "institutional knowledge"
+that's lost when the message limit is reached.
+
+The Slack Archiver seeks to remedy this situation by extracting the history 
+for specific channels to an database or file. Messges could be extracted up to
+the maximum allowed limit of 50 messages per minute for the `channels.history` 
+API method. At this rate (tier 4) 86.4K messages could be theorectically
+retrieved per day.
+
+Implementors are cautioned that further research will be required to
+determine the best extraction method to use prior to attempting any 
+development of this application.
+
+## User Stories
+
+-   [ ] Allow the user to specify the channels to be archived. This includes
+both adding and removing channels from the list
+-   [ ] Only the owners of the Slack Team should be allowed to archive
+messages
+-   [ ] For each channel to be archived periodically extract messages starting
+from the last message retrieved in the last extract and write them to  a database).
+-   [ ] Allow the user to copy and extracted channel to a file 
+-   [ ] Archiving should be an automatic process. Unlike a Slack 'bot, no
+manual intervention should be required to start or stop and archive operation.
+
+## Bonus features
+
+-   [ ] Implememnt an API that allows an application to extract archived messages
+from the archive database
+
+## Useful links and resources
+
+Details of the Slack API can be found [here](https://api.slack.com/).
+
+## Example projects
+
+For an example of a commercial archiving application for Slack see
+[Chronicle](https://chingu-prework.slack.com/apps/A47KWM6Q4-chronicle)

README.md

@@ -28,6 +28,7 @@ Each project has the following **features**:
 | [Book Finder App](./Projects/Book-Finder-App.md)                   |
 | [Kudos Slackbot](./Projects/Kudos-Slackbot.md)                     |
 | [Markdown Table Generator](./Projects/Markdown-Table-Generator.md) |
+| [Slack Archiver](./Projects/Slack-Archiver.md)                     |
 
 ### Contribution