Fix issue where lowercased "write" SQL queries would get sent to replica

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    janus-ar (0.11.0)
+    janus-ar (0.13.0)
 
 GEM
   remote: http://rubygems.org/

lib/active_record/connection_adapters/janus_mysql2_adapter.rb

@@ -133,7 +133,7 @@ def send_to_replica(sql, connection: nil, method: :exec_query)
       end
 
       def write_query?(sql)
-        WRITE_PREFIXES.include?(sql.split(' ').first)
+        WRITE_PREFIXES.include?(sql.upcase.split(' ').first)
       end
 
       def update_config

lib/janus/version.rb

@@ -4,7 +4,7 @@ module Janus
   unless defined?(::Janus::VERSION)
     module VERSION
       MAJOR = 0
-      MINOR = 12
+      MINOR = 13
       PATCH = 0
       PRE = nil
 

spec/lib/active_record/connection_adapters/janus_mysql_adapter_spec.rb

@@ -121,5 +121,25 @@
         expect($query_logger.queries.first).to include '[primary]'
       end
     end
+
+    describe 'INSERT' do
+      let(:insert_query) { 'INSERT INTO test_table SET `id` = 5;' }
+
+      before(:each) do
+        create_test_table
+        $query_logger.flush_all
+        Janus::Context.release_all
+      end
+
+      it 'sends INSERT query to primary' do
+        ActiveRecord::Base.connection.execute(insert_query)
+        expect($query_logger.queries.first).to include '[primary]'
+      end
+
+      it 'ignores case when directing queries' do
+        ActiveRecord::Base.connection.execute(insert_query.downcase)
+        expect($query_logger.queries.first).to include '[primary]'
+      end
+    end
   end
 end