Add ruby 2.4

.rubocop.yml

@@ -171,6 +171,10 @@ Rails/TimeZone:
   Exclude:
     - "spec/lib/**/*"
 
+Rails/Delegate:
+  Exclude:
+    - "lib/**/*"
+
 Style/SingleLineMethods:
   Exclude:
     - "test/dummy/app/models/*"
@@ -181,13 +185,17 @@ Style/EmptyLineBetweenDefs:
 Style/NumericPredicate:
   EnforcedStyle: comparison
 
+### backward compatibility
+
+# only with ruby >= 2.3
 Style/FrozenStringLiteralComment:
   Enabled: false
 
-Rails/Delegate:
+# only with ruby >= 2.4
-  Exclude:
+Performance/RegexpMatch:
-    - "lib/**/*"
+  Enabled: false
 
+# for rails 4 and ruby < 2.2.2
 Rails/HttpPositionalArguments:
   Exclude:
     - "spec/controllers/diaspora_federation/fixtures_rails4_spec.rb"

.ruby-version

@@ -1 +1 @@
-2.3
+2.4

.travis.yml

@@ -1,6 +1,7 @@
 language: ruby
 
 rvm:
+  - 2.4.0
   - 2.3.3
   - 2.2.5
   - 2.1

Gemfile.lock

@@ -321,4 +321,4 @@ DEPENDENCIES
   yard
 
 BUNDLED WITH
-   1.13.6
+   1.13.7