Added kubernetes and docker swarm to main TOC. (#497)

docs/operating/databases/README.md

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+
+# Databases
+
+We currently support the following databases and they are passed in via the `DB_URL` environment variable. For example:
+
+```sh
+docker run -e "DB_URL=postgres://user:pass@localhost:6212/mydb" ...
+```
+
+## [Bolt](https://github.com/boltdb/bolt) (default)
+
+URL: `bolt:///functions/data/functions.db`
+
+Bolt is an embedded database which stores to disk. If you want to use this, be sure you don't lose the data directory by mounting
+the directory on your host. eg: `docker run -v $PWD/data:/functions/data -e DB_URL=bolt:///functions/data/bolt.db ...`
+
+[More on BoltDB](boltdb.md)
+
+## [PostgreSQL](http://www.postgresql.org/)
+
+URL: `postgres://user123:pass456@ec2-117-21-174-214.compute-1.amazonaws.com:6212/db982398`
+
+Use a PostgreSQL database. If you're using IronFunctions in production, you should probably start here.
+
+[More on Postgres](postgres.md)
+
+## What about database X?
+
+We're happy to add more and we love pull requests, so feel free to add one! Copy one of the implementations above as a starting point. 
+