docs: Improve readme

README.md

@@ -1,2 +1,25 @@
 # pgtrail
 Auditing system for PostgreSQL
+
+# Description
+
+It creates new schema `pgtrail` which contains required functions and default audit storage table.
+You can use function `pgtrail.enable_audit('public.table_name')` for starting auditing changes of a table.
+This function will add a trigger to your table, which will be call on inserts, updates or deletes and will log
+all the information to default storage table `pgtrail.audit_changes`.
+
+You can see an example, by going to `examples/` and running `./run_example_docker.sh`. Example creates a table `employees`
+and fills it with some test data, after which applies some changes so audit is generated. The script will build docker container 
+for the example, start it in detached mode and then would put you into `psql` tools where you can tinker with the database.
+For example, you can run `SELECT * FROM pgtrail.audit_changes;` to see all existing change. Alternatively you can use
+your favourite database management tool to connect to the container on standard port 5432.
+
+# Roadmap
+- Tests
+- Benchmarks
+- Implement functions to get state of a record at given time (by applying changes)
+- Implement automatic creation of storage table if it doesn't exist yet
+- Partitioning
+- Explore option for removing requirement of object_id to be uuid
+- Make it an extension (?)
+- Explore option for json metadata passing through transaction level 'current_setting("metadata)', fx for tracing id