Merge pull request apache#4 from OpenLineage/readme

Adding README

README.md

@@ -1 +1,32 @@
-# OpenLineage
+# OpenLineage
+
+## Overview
+OpenLineage is an Open standard for metadata and lineage collection designed to instrument jobs as they are running.
+It defines a generic model of run, job, and dataset entities identified using consistent naming strategies.
+The core lineage model is extensible by defining specific facets to enrich those entities.
+
+## Problem
+ ![Problem](doc/problem.png)
+
+### Before
+- Duplication of effort: Each project has to instrument all jobs
+- Integrations are external and can break with new versions
+
+### With OpenLineage
+- Effort of integration is shared
+- Integration can be pushed in each project: no need to play catch up
+
+## Scope
+OpenLineage defines the metadata for running jobs and the corresponding events.
+A configurable backend allows to choose what protocol to send the events to.
+ ![Scope](doc/Scope.png)
+
+## Core model
+
+ ![Model](doc/OpenLineageModel.svg)
+
+ A facet is an atomic piece of metadata attached to one of the core entities.
+ See the spec for more details.
+
+## Spec
+The [specification](spec/OpenLineage.md) is defined using OpenAPI and allows extension through custom facets.