README.md in prawn-emoji-3.1.0 vs README.md in prawn-emoji-3.2.0

@@ -1,9 +1,9 @@
 # Prawn::Emoji
 
+[![Test](https://github.com/hidakatsuya/prawn-emoji/workflows/Test/badge.svg?branch=master)](https://github.com/hidakatsuya/prawn-emoji/actions)
 [![Gem Version](https://badge.fury.io/rb/prawn-emoji.svg)](https://badge.fury.io/rb/prawn-emoji)
-[![Build Status](https://travis-ci.org/hidakatsuya/prawn-emoji.svg)](https://travis-ci.org/hidakatsuya/prawn-emoji)
 [![Maintainability](https://api.codeclimate.com/v1/badges/edcd23ef38c2e393513b/maintainability)](https://codeclimate.com/github/hidakatsuya/prawn-emoji/maintainability)
 
 Prawn::Emoji is an extention that adds Emoji support to [Prawn](https://github.com/prawnpdf/prawn).
 
 ```ruby
@@ -65,15 +65,30 @@
 
 ### True Type Font Required
 
 In order to draw Emoji, you must use a True Type Font. I recommend you use a Japanese font.
 
+## Configuring Emoji Regex
+
+Emoji Regex is a regular expression used to determine which emoji to draw.
+
+```ruby
+Prawn::Emoji.config.regex # => ::Unicode::Emoji::REGEX_VALID by default
+```
+
+You can override it with [unicode-emoji's Regex](https://github.com/janlelis/unicode-emoji#regex):
+
+```ruby
+Prawn::Emoji.config.regex = ::Unicode::Emoji::REGEX_INCLUDE_TEXT
+```
+
+
 ## Supported Versions
 
 ### Ruby
 
-2.4, 2.5, 2.6
+2.4, 2.5, 2.6, 2.7
 
 ### Prawn
 
 2.2+
 
@@ -103,24 +118,26 @@
 $ bundle exec rake test:pdf
 ```
 
 In order to run `test:pdf`, you need to install [diff-pdf](https://github.com/vslavik/diff-pdf) in your environment, or you can run test in the docker container as below.
 
-### Run test using the Docker container
+### How to develop in Docker container
 
-The `diff-pdf` is already installed on the Docker container, so there is no need to install it in your environment.
+You can use the Docker container for development. This container contains the libraries required for testing, such as diff-pdf.
 
 ```
-$ docker build -t prawn-emoji-test .
+$ docker build -t prawn-emoji-dev .
 
-# Run test:pdf by default
-$ docker run --rm prawn-emoji-test
+$ docker run -v $PWD:/prawn-emoji -it prawn-emoji-dev bash
 
-# Run test:units
-$ docker run --rm prawn-emoji-test test:units
+> /prawn-emoji#
+```
 
-# Run all test
-$ docker run --rm prawn-emoji-test test
+You can run test:
+
+```
+> /prawn-emoji# bundle install
+> /prawn-emoji# bundle exec rake test
 ```
 
 ### How to update bundled emojis
 
 ```