Update gemspec: remove non needed files

gems.rb

@@ -1,4 +1,3 @@
 source 'https://rubygems.org'
 
-# Specify your gem's dependencies in journald-logger.gemspec
 gemspec

journald-native.gemspec

@@ -8,13 +8,17 @@ Gem::Specification.new do |spec|
   spec.version       = Journald::Native::VERSION
   spec.authors       = ['Anton Smirnov']
   spec.email         = ['sandfox@sandfox.me']
-  spec.summary       = %q{systemd-journal logging native lib wrapper}
-  # spec.description   = %q{Write a longer description. Optional.}
+  spec.summary       = 'systemd-journal logging native lib wrapper'
   spec.homepage      = 'https://github.com/sandfoxme/journald-native'
   spec.license       = 'LGPL-2.1+'
 
-  spec.files         = `git ls-files -z`.split("\x0")
-  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
+  spec.files         =
+    # Get all files from git
+    # Do not include full text of the license (there is a link),
+    # dot files, tests
+    `git ls-files -z`
+    .split("\x0")
+    .reject{ |file| %r{^(COPYING|\.|spec/)}.match? file }
   spec.require_paths = ['lib']
 
   spec.extensions << 'ext/journald_native/extconf.rb'
@@ -25,4 +29,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'rake-compiler'
   spec.add_development_dependency 'rspec', '~> 3.4'
+
+  spec.requirements << 'systemd-journal'
+  spec.requirements << 'systemd development package'
 end