📝 Update README with instructions

Also made the linter happy (line length)

Makefile

@@ -1,3 +1,3 @@
 release:
 	rake build
-	gem push pkg/percy-selenium-*
+	gem push pkg/percy-capybara-*

README.md

@@ -1,6 +1,102 @@
-# Percy Capybara
+# percy-capybara
+[![Gem Version](https://badge.fury.io/rb/percy-selenium.svg)](https://badge.fury.io/rb/percy-capybara)
+![Test](https://github.com/percy/percy-capybara/workflows/Test/badge.svg)
 
-[![CircleCI](https://circleci.com/gh/percy/percy-capybara.svg?style=svg)](https://circleci.com/gh/percy/percy-capybara)
-[![Gem Version](https://badge.fury.io/rb/percy-capybara.svg)](http://badge.fury.io/rb/percy-capybara)
+[Percy](https://percy.io) visual testing for Ruby Selenium.
 
-#### Docs here: [https://docs.percy.io/docs/capybara](https://docs.percy.io/docs/capybara)
+## Installation
+
+npm install `@percy/cli`:
+
+```sh-session
+$ npm install --save-dev @percy/cli
+```
+
+gem install Percy selenium package:
+
+```ssh-session
+$ gem install percy-capybara
+```
+
+## Usage
+
+In your test setup file, require `percy/capybara`. For example if you're using
+rspec, you would add the following to your `spec_helper.rb` file:
+
+
+``` ruby
+require 'percy/capybara'
+```
+
+Now you can use `page.percy_snapshot` to capture snapshots.
+
+> Note: Percy requires JS to be enabled for snapshots to be captured.
+
+```ruby
+describe 'my feature, type: :feature, js: true do
+  it 'renders the page' do
+    visit 'https://example.com'
+    page.percy_snapshot('Example snapshot')
+  end
+end
+```
+
+
+Running the test above normally will result in the following log:
+
+```sh-session
+[percy] Percy is not running, disabling snapshots
+```
+
+When running with [`percy
+exec`](https://github.com/percy/cli/tree/master/packages/cli-exec#percy-exec), and your project's
+`PERCY_TOKEN`, a new Percy build will be created and snapshots will be uploaded to your project.
+
+```sh-session
+$ export PERCY_TOKEN=[your-project-token]
+$ percy exec -- [test command]
+[percy] Percy has started!
+[percy] Created build #1: https://percy.io/[your-project]
+[percy] Snapshot taken "Ruby example"
+[percy] Stopping percy...
+[percy] Finalized build #1: https://percy.io/[your-project]
+[percy] Done!
+```
+
+## Configuration
+
+`page.snapshot(name[, options])`
+
+- `name` (**required**) - The snapshot name; must be unique to each snapshot
+- `options` - [See per-snapshot configuration options](https://docs.percy.io/docs/cli-configuration#per-snapshot-configuration)
+
+## Upgrading
+
+### Manually
+
+#### Require change
+
+The name of the require has changed from `require 'percy'` to `require
+'percy/capybara'`. This is to avoid conflict with our [Ruby Selenium SDK's require](https://github.com/percy/percy-selenium-ruby)
+statement.
+
+#### Installing `@percy/cli` & removing `@percy/agent`
+
+If you're coming from a pre-3.0 version of this package, make sure to install `@percy/cli` after
+upgrading to retain any existing scripts that reference the Percy CLI
+command. You will also want to uninstall `@percy/agent`, as it's been replaced
+by `@percy/cli`.
+
+```sh-session
+$ npm uninstall @percy/agent
+$ npm install --save-dev @percy/cli
+```
+
+#### Migrating config
+
+If you have a previous Percy configuration file, migrate it to the newest version with the
+[`config:migrate`](https://github.com/percy/cli/tree/master/packages/cli-config#percy-configmigrate-filepath-output) command:
+
+```sh-session
+$ percy config:migrate
+```

spec/lib/percy/percy_capybara_spec.rb

@@ -1,3 +1,5 @@
+LABEL = PercyCapybara::PERCY_LABEL
+
 RSpec.describe PercyCapybara, type: :feature do
   before(:each) do
     WebMock.disable_net_connect!(allow: '127.0.0.1', disallow: 'localhost')
@@ -10,7 +12,7 @@
         .to_return(status: 200, body: '', headers: {'x-percy-core-version': '0.1.0'})
 
       expect { page.percy_snapshot('Name') }
-        .to output("#{PercyCapybara::PERCY_LABEL} Unsupported Percy CLI version, 0.1.0\n").to_stdout
+        .to output("#{LABEL} Unsupported Percy CLI version, 0.1.0\n").to_stdout
     end
 
     it 'disables when healthcheck version is missing' do
@@ -19,7 +21,7 @@
 
       expect { page.percy_snapshot('Name') }
         .to output(
-          "#{PercyCapybara::PERCY_LABEL} You may be using @percy/agent which" \
+          "#{LABEL} You may be using @percy/agent which" \
           ' is no longer supported by this SDK. Please uninstall' \
           ' @percy/agent and install @percy/cli instead.' \
           " https://docs.percy.io/docs/migrating-to-percy-cli\n",
@@ -31,15 +33,15 @@
         .to_return(status: 500, body: '', headers: {})
 
       expect { page.percy_snapshot('Name') }
-        .to output("#{PercyCapybara::PERCY_LABEL} Percy is not running, disabling snapshots\n").to_stdout
+        .to output("#{LABEL} Percy is not running, disabling snapshots\n").to_stdout
     end
 
     it 'disables when healthcheck fails to connect' do
       stub_request(:get, "#{PercyCapybara::PERCY_SERVER_ADDRESS}/percy/healthcheck")
         .to_raise(StandardError)
 
       expect { page.percy_snapshot('Name') }
-        .to output("#{PercyCapybara::PERCY_LABEL} Percy is not running, disabling snapshots\n").to_stdout
+        .to output("#{LABEL} Percy is not running, disabling snapshots\n").to_stdout
     end
 
     it 'throws an error when name is not provided' do
@@ -64,7 +66,7 @@
         .to_return(status: 200, body: '', headers: {})
 
       expect { page.percy_snapshot('Name') }
-        .to output("#{PercyCapybara::PERCY_LABEL} Could not take DOM snapshot 'Name'\n").to_stdout
+        .to output("#{LABEL} Could not take DOM snapshot 'Name'\n").to_stdout
     end
 
     it 'sends snapshots to the local server' do