Update roadmap for 2020 🛣️

In tektoncd/community#77 we started on a roadmap
for 2020 for all of Tekton but folks pointed out it makes more sense to
let each project's own roadmap live in the repo with them.

README.md

@@ -28,6 +28,7 @@ Tekton Pipelines are **Typed**:
 
 - [Installing Tekton Pipelines](docs/install.md)
 - Jump in with [the tutorial!](docs/tutorial.md)
+- Take a look at our [roadmap](roadmap.md)
 
 *Note that starting from the 0.11 release of Tetkon, you need to have
 a cluster with **Kubernetes version 1.15 or later***.

roadmap.md

@@ -0,0 +1,81 @@
+# Tekton Pipelines 2020 Roadmap
+
+This is an incomplete list of work we hope to accomplish in 2020.
+
+Highlights:
+
+- [Tekton mission and vision](https://github.com/tektoncd/community/blob/master/roadmap.md#mission-and-vision)
+- ["Feature complete"](#feature-complete)
+- [Beta for all components](#beta-for-all-components)
+- [Task interfaces and PipelineResources](#task-interfaces-and-pipelineresources)
+- [SCM support](#scm-support)
+
+## "Feature complete"
+
+Today Tekton can do basically anything you want it to, but there are a few features
+still missing or not quite where we want them. Once we have these features, folks
+should be able to use Tekton for all of their CI/CD use cases.
+
+Deciding what to support and what to expect users to write into their own `Tasks`
+is a constant balancing act, and we want to be careful and deliberate with what we
+include.
+
+Features we don't have or aren't yet 100% satisfied with for "feature complete"
+Tekton:
+
+- [Failure strategies](https://github.com/tektoncd/pipeline/issues/1684)
+- [Conditional execution](https://github.com/tektoncd/pipeline/blob/master/docs/conditions.md)
+  - we will continue to iterate on this functionality as we add failure strategies
+- [Pause and resume](https://github.com/tektoncd/pipeline/issues/233)
+- [Partial execution](https://github.com/tektoncd/pipeline/issues/50)
+- [Notifications](https://github.com/tektoncd/pipeline/issues/1740)
+- [`Task` Versioning](https://github.com/tektoncd/pipeline/issues/1839) - Also required
+  for [Catalog](#catalog) success
+- [Alternative Task Implementations](https://github.com/tektoncd/pipeline/issues/215)
+- [Local Execution](https://github.com/tektoncd/pipeline/issues/235)
+- [Testing](https://github.com/tektoncd/pipeline/issues/1289) and [debugging](https://github.com/tektoncd/pipeline/issues/2069) frameworks
+- [Emiting events throughout `Pipeline`
+  execution](https://github.com/tektoncd/pipeline/issues/2082)
+- [Config as code](https://github.com/tektoncd/pipeline/issues/859) - This has some cross
+  over with [a related Triggers issue](https://github.com/tektoncd/triggers/issues/189)
+- [Performant Tekton](https://github.com/tektoncd/pipeline/issues/540) - We should set
+  performance requirements and measure against them
+- [Adding support for other architectures](https://github.com/tektoncd/pipeline/issues/856)
+- [Rich type support for params](https://github.com/tektoncd/pipeline/issues/1393)
+- Looping syntax (in [Tasks](https://github.com/tektoncd/pipeline/issues/2112) and/or [Pipelines](https://github.com/tektoncd/pipeline/issues/2050))- either implement or decide it is outside of scope (i.e. better suited for a DSL)
+
+## Beta for all components
+
+In early 2020 we will have our first beta release, however
+[it will be only for a subset of Pipeline's resources](https://docs.google.com/document/d/1H8I2Rk4kLdQaR4mV0A71Qbk-1FxXFrmvisEAjLKT6H0/edit#heading=h.t0sc4hdrr5yq).
+After the intial beta release, we would like to get the rest of the resources to beta
+as well.
+
+## Task Interfaces and PipelineResources
+
+In alpha Tekton Pipelines, [`PipelineResources`](https://github.com/tektoncd/pipeline/issues/1673)
+were the interface between `Tasks` in a `Pipeline`: they were used for sharing typed
+data and variables between `Tasks`. This is being revisited and the feature has been
+deconstructed into:
+
+* `workspaces` - A way for a `Task` to declare data it needs and provides without
+  needing to know about the underlying mechanism used
+* `Task results` (aka "output params") - A way for a `Task` to provide values as outputs
+  which can be provided to downstream `Tasks`
+
+After adding these features we will once again reconsider the design of `PipelineResources`
+and decide what additional features, if any, we need.
+
+We will also need to decide how to continue to release and maintain the code that
+is used to build the images used by the existing `PipelineResources`:
+https://github.com/tektoncd/pipeline/tree/master/cmd.
+
+## SCM support
+
+SCM support in 2019 was handled by
+[the PullRequest Resource](https://github.com/tektoncd/pipeline/blob/master/docs/resources.md#pull-request-resource).
+However [we are revisting PipelineResources](#task-interfaces-and-pipelineresources),
+and likely this `PipelineResource` will become one or more `Tasks` in
+[the catalog](https://github.com/tektoncd/catalog) instead. Once that happens,
+we will need to make decisions about how to release and maintain the
+supporting code.