Create Actions Walkthrough (#36)

* starting walkthrough docs

* versioning

docs/action-types.md

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+# Action Types
+
+There are two types of actions.  JavaScript and Docker actions.
+
+- **JavaScript Actions**: JavaScript actions run on the host machine.  The unit of work is decoupled from the environment.
+- **Docker Actions**: A container action is a container which carries both the unit of work along with the environment and it's dependencies packaged up as a container.
+
+Both have access to the workspace and the github event payload and context.
+
+## Why would I choose a Docker action?
+
+Docker actions carry both the unit of work and the environment.
+
+This creates a more consistent and reliable unit of work where the consumer of the action does not need to worry about the toolsets and it's dependencies.
+
+Docker actions are currently limited to Linux only.
+
+## Why would I choose a host action?
+
+JavaScript actions decouple the unit of work from the environment and run directly on the host machine or VM.
+
+Consider a simple example of testing a node lib on node 8, 10 and running a custom action.  Each job will setup a node version on the host and custom-action will run it's unit of work on each environment (node8+ubunut16, node8+windows-2019, etc.)
+
+```yaml
+on: push
+
+jobs:
+  build:
+    strategy: 
+      matrix:
+        node: [8.x, 10.x]
+        os: [ubuntu-16.04, windows-2019]
+    runs-on: ${{matrix.os}}
+    actions:
+    - uses: actions/setup-node@master
+      with:
+        version: ${{matrix.node}}
+    - run: | 
+        npm install
+    - run: |
+        npm test
+    - uses: actions/custom-action@master
+```
+
+JavaScript actions work on any environment that host action runtime is supported on which is currently node 12.  However, a host action that runs a toolset expects the environment that it's running on to have that toolset in it's PATH or using a setup-* action to acquire it on demand.