update ruby version 2.3.1 to ruby 2.3.4

.ruby-version

@@ -1 +1 @@
-2.3.1
+2.3.4

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby '2.3.1'
+ruby '2.3.4'
 
 gem 'rails',                      '4.2.6'
 

Gemfile.lock

@@ -525,7 +525,7 @@ DEPENDENCIES
   underscore-rails (= 1.8.3)
 
 RUBY VERSION
-   ruby 2.3.1p112
+   ruby 2.3.4p112
 
 BUNDLED WITH
    1.15.1

README.md

@@ -25,7 +25,7 @@ We use the wonderful [Contributor Covenant](http://contributor-covenant.org) for
 
 # Installation
 
-The app uses  **Ruby 2.3.1** and **Rails 4.2.6**. Please stick to these versions.
+The app uses  **Ruby 2.3.4** and **Rails 4.2.6**. Please stick to these versions.
 
 The steps below should be straightforward for Linux and macOS users. Windows users please refer to this [guide](https://gist.github.com/KelseyDH/11198922) for tips on setup.
 
@@ -50,7 +50,7 @@ rvm get stable --autolibs=enable
 **Close and re-open the terminal window**
 
 ```
-rvm install ruby-2.3.1
+rvm install ruby-2.3.4
 ```
 
 Check that Ruby has been updated by running `ruby -v`.
@@ -59,13 +59,13 @@ Check that Ruby has been updated by running `ruby -v`.
 
 Follow instructions for updating rbenv at the project's [GitHub](https://github.com/rbenv/rbenv). Make sure you also upgrade `ruby-build` if you used Homebrew to install rbenv.
 
-Run the following to install Ruby 2.3.1:
+Run the following to install Ruby 2.3.4:
 
 ```
 rbenv install 2.3.1
 ```
 
-Once you have cloned the project, set the local Ruby version to 2.3.1:
+Once you have cloned the project, set the local Ruby version to 2.3.4:
 
 ```
 cd ifme
@@ -93,7 +93,7 @@ Make a gemset for the specific Ruby on Rails version through RVM or rbenv. Conti
 #### option (A) RVM
 
 ```
-rvm use ruby-2.3.1@rails4.2.6 --create
+rvm use ruby-2.3.4@rails4.2.6 --create
 ```
 
 #### option (B) rbenv

circle.yml

@@ -1,6 +1,6 @@
 machine:
   ruby:
-    version: 2.3.1
+    version: 2.3.4
 
 dependencies:
   pre: