Bump to 2.5.1

.travis.yml

@@ -29,7 +29,7 @@
 language: ruby
 
 rvm:
-  - 2.5.0
+  - 2.5.1
 
 sudo: required
 dist: trusty

Gemfile

@@ -28,7 +28,7 @@
 
 source 'https://rubygems.org'
 
-ruby '~> 2.5.0'
+ruby '~> 2.5.1'
 
 gem 'actionpack-xml_parser', '~> 2.0.0'
 gem 'activemodel-serializers-xml', '~> 1.0.1'

Gemfile.lock

@@ -723,7 +723,7 @@ DEPENDENCIES
   will_paginate (~> 3.1.0)
 
 RUBY VERSION
-   ruby 2.5.0p0
+   ruby 2.5.1p57
 
 BUNDLED WITH
    1.16.1

docs/development/development-environment-ubuntu.md

@@ -22,7 +22,7 @@ We need an active Ruby and Node JS environment to run OpenProject. To this end,
 
 ## Install Ruby 2.5.
 
-Use [rbenv](https://github.com/rbenv/rbenv) and [ruby-build](https://github.com/rbenv/ruby-build#readme) to install Ruby 2.5.0.
+Use [rbenv](https://github.com/rbenv/rbenv) and [ruby-build](https://github.com/rbenv/ruby-build#readme) to install Ruby 2.5.
 
 
 **Install rbenv**
@@ -61,13 +61,13 @@ and install that version.
 
 ```bash
 # Install the required version as read from the Gemfile
-[dev@ubuntu]# rbenv install 2.5.0
+[dev@ubuntu]# rbenv install 2.5.1
 ```
 
 This might take a while depending on whether ruby is built from source. After it is complete, you need to tell rbenv to globally activate this version
 
 ```bash
-[dev@ubuntu]# rbenv global 2.5.0
+[dev@ubuntu]# rbenv global 2.5.1
 ```
 
 You also need to install [bundler](https://github.com/bundler/bundler/), the ruby gem bundler.
@@ -144,7 +144,7 @@ You should now have an active ruby and node installation. Verify that it works w
 
 ```bash
 [dev@ubuntu]# ruby --version
-ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin16]
+ruby 2.5.1p57 (2017-12-25 revision 61468) [x86_64-darwin16]
 
 [dev@ubuntu]# bundler --version
 Bundler version 1.16.1

docs/installation/system-requirements.md

@@ -26,7 +26,7 @@ provide any official support for them.
 
 ### Dependencies
 
-* __Runtime:__ [Ruby](https://www.ruby-lang.org/en/) Version = 2.5.0
+* __Runtime:__ [Ruby](https://www.ruby-lang.org/en/) Version = 2.5.1
 * __Webserver:__ [Apache](http://httpd.apache.org/)
   or [nginx](http://nginx.org/en/docs/)
 * __Application server:__ [Phusion Passenger](https://www.phusionpassenger.com/)