[workflow] add Travis CI

.travis.yml

@@ -1,6 +1,5 @@
 language: crystal
 
-# Uncomment the following if you'd like Travis to run specs and check code formatting
-# script:
-#   - crystal spec
-#   - crystal tool format --check
+script:
+  - crystal spec
+  - crystal tool format --check

README.md

@@ -1,6 +1,6 @@
 # validator
 
-[![GitHub release](https://img.shields.io/github/release/Nicolab/crystal-validator.svg)](https://github.com/Nicolab/crystal-validator/releases) [![Docs](https://img.shields.io/badge/docs-available-brightgreen.svg)](https://nicolab.github.io/crystal-validator/)
+[![Build Status](https://travis-ci.com/Nicolab/crystal-validator.svg?branch=master)](https://travis-ci.com/Nicolab/crystal-validator) [![GitHub release](https://img.shields.io/github/release/Nicolab/crystal-validator.svg)](https://github.com/Nicolab/crystal-validator/releases) [![Docs](https://img.shields.io/badge/docs-available-brightgreen.svg)](https://nicolab.github.io/crystal-validator/)
 
 ∠(・.-)―〉 →◎ `validator` is a [Crystal](https://crystal-lang.org) micro validations module.<br>
 Very simple and efficient, all validations return `true` or `false`.

src/validator.cr

@@ -83,7 +83,7 @@ require "./validators/*"
 #
 # `Check` is a simple and lightweight wrapper, let your imagination run wild to add your logic around it.
 module Validator
-  VERSION = "1.0.0-rc4"
+  VERSION = "1.0.0-rc5"
 
   # Used by `is!` when a validation is not `true`.
   class Error < Exception; end