[Docs] Update README for the Client release (#68)

* Update README for the Client release

* Remove http: from URL in README

* Add a not on TLS support

Author: antstorm

README.md

@@ -1,15 +1,94 @@
 # Temporal Ruby SDK
 
-![CI status](https://github.com/temporalio/sdk-ruby/actions/workflows/ci.yml/badge.svg?branch=main)
+[![CI status](https://github.com/temporalio/sdk-ruby/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/temporalio/sdk-ruby/actions/workflows/ci.yml?query=branch%3Amain)
+[![Build](https://github.com/temporalio/sdk-ruby/actions/workflows/build-native-ext.yml/badge.svg)](https://github.com/temporalio/sdk-ruby/actions/workflows/build-native-ext.yml?query=branch%3Amain+event%3Arelease)
+[![Gem Version](https://badge.fury.io/rb/temporalio.svg)](https://rubygems.org/gems/temporalio)
 
-Temporal is a distributed, scalable, durable, and highly available orchestration engine used to
-execute asynchronous long-running business logic in a scalable and resilient way.
+[Temporal](https://temporal.io/) is a distributed, scalable, durable, and highly available
+orchestration engine used to execute asynchronous long-running business logic in a scalable and
+resilient way.
 
 "Temporal Ruby SDK" is the framework for authoring workflows and activities using the Ruby
 programming language.
 
 ⚠️ UNDER DEVELOPMENT
 
+The Ruby SDK is under development. There are no compatibility guarantees at this time.
+
+At this point the SDK only supports the **Temporal Client** capabilities:
+
+- Starting a workflow (defined in any other SDK)
+- Interacting with a workflow (cancelling, querying, signalling, etc)
+- Interceptor and Data Conversion support
+- gRPC access to Temporal Server
+- Temporal Cloud is not yet supported due to the lack of TLS support, but it's coming soon
+
+
+## Quick Start
+
+### Installation
+
+Add the [`temporalio` gem](https://rubygems.org/gems/temporalio) to your Gemfile:
+
+```ruby
+gem 'temporalio'
+```
+
+The SDK is now ready for use. To build from source, see [Dev Setup](#dev-setup).
+
+**NOTE: This README is for the current branch and not necessarily what's released on RubyGems.**
+
+
+## Usage
+
+### Client
+
+A client can be created and used to start a workflow like so:
+
+```ruby
+# Establish a gRPC connection to the server
+connection = Temporal::Connection.new('localhost:7233')
+
+# Initialize a Client with a namespace
+client = Temporal::Client.new(connection, 'my-namespace')
+
+# Start a workflow
+handle = client.start_workflow('MyWorkflow', 'some input', id: 'my-id', task_queue: 'my-task-queue')
+
+# Wait for the workflow to finish processing
+result = handle.result
+puts "Result: #{result}"
+```
+
+Some things to note about the above code:
+
+- A `Client` does not have an explicit "close"
+- TLS is not yet supported
+- All positional arguments after the workflow name are treated as workflow arguments
+- The `handle` represents the workflow that was started and can be used for more than just getting
+  the result
+- Clients can have many more options not shown here (e.g. data converters and interceptors)
+
+### Data Conversion
+
+Data converters are used to convert raw Temporal payloads to/from actual Ruby types. These consist
+of 3 distinct types of converters:
+
+- **Payload Converters** to convert Ruby values to/from serialized bytes
+- **Payload Codecs** to convert bytes to bytes (e.g. for compression or encryption)
+- **Failure Converters** to convert exceptions to/from serialized failures
+
+The default data converter supports converting multiple types including:
+
+- `nil`
+- bytes (`String` with `Encoding::ASCII_8BIT`)
+- Anything that [`JSON.generate`](https://ruby-doc.org/stdlib-3.0.0/libdoc/json/rdoc/JSON.html#method-i-generate)
+  supports
+
+This notably doesn't include any `Date`, `Time`, or `DateTime` objects as they may not work across
+different SDKs. A custom payload converter can be implemented to support these.
+
+
 ## Dev Setup
 
 Once you've forked/cloned the repository you want to make sure all the submodules are fetched as
@@ -41,11 +120,11 @@ Now you should be able to compile a dev build of the Bridge:
 You can then run all the specs against a dev build using:
 
 ```sh
-> DEBUG=true bundle exec rspec
+> bundle exec rspec
 ```
 
 And open an IRB session using:
 
 ```sh
-> DEBUG=true bundle console
+> bundle console
 ```