Remove coveralls dependency

Gemfile

@@ -7,14 +7,13 @@ group :development do
 end
 
 group :test do
-  gem "coveralls"
   gem "rb-readline", ">= 0.5.5"
   gem "rspec", ">= 3"
   gem "rubocop", ">= 0.79"
   gem "rubocop-performance"
   gem "rubocop-rake"
   gem "rubocop-rspec"
-  gem "simplecov", ">= 0.18.2"
+  gem "simplecov", ">= 0.16"
   gem "timecop"
   gem "tins"
   gem "webmock", ">= 3.8.2"

README.md

@@ -5,13 +5,11 @@
 [![Gem Version](https://img.shields.io/gem/v/t.svg)][gem]
 [![Build Status](https://img.shields.io/travis/sferik/t.svg)][travis]
 [![Dependency Status](https://img.shields.io/gemnasium/sferik/t.svg)][gemnasium]
-[![Coverage Status](https://img.shields.io/coveralls/sferik/t.svg)][coveralls]
 [![tip for next commit](https://tip4commit.com/projects/102.svg)](https://tip4commit.com/github/sferik/t)
 
 [gem]: https://rubygems.org/gems/t
 [travis]: https://travis-ci.org/sferik/t
 [gemnasium]: https://gemnasium.com/sferik/t
-[coveralls]: https://coveralls.io/r/sferik/t
 
 #### A command-line power tool for Twitter.
 The CLI takes syntactic cues from the [Twitter SMS commands][sms], but it

spec/helper.rb

@@ -1,9 +1,6 @@
 ENV["THOR_COLUMNS"] = "80"
 
 require "simplecov"
-require "coveralls"
-
-SimpleCov.formatters = [SimpleCov::Formatter::HTMLFormatter, Coveralls::SimpleCov::Formatter]
 
 SimpleCov.start do
   add_filter "/spec"