title: Error while creating a Redis object and executing commands when calling methods
body: <p>This is the output of my rails console after I include rubygems and redis.</p>
  
  <pre><code>2.0.0-p353 :024 &gt; r = Redis.new
  =&gt; #&lt;Redis client v3.0.7 for redis://127.0.0.1:6379/0&gt; 
  2.0.0-p353 :025 &gt; r.set('foo','bar')
  =&gt; "OK" 
  2.0.0-p353 :026 &gt; r.get('foo')
  =&gt; "bar"
  2.0.0-p353 :033 &gt; r.lpush('foo','bar')
  Redis::CommandError: ERR Operation against a key holding the wrong kind of value
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/redis-3.0.7/lib/redis/client.rb:97:in `call'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/redis-3.0.7/lib/redis.rb:949:in `block in lpush'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/redis-3.0.7/lib/redis.rb:37:in `block in synchronize'
  from /home/poorva/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/redis-3.0.7/lib/redis.rb:37:in `synchronize'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/redis-3.0.7/lib/redis.rb:948:in `lpush'
  from (irb):33
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands/console.rb:90:in `start'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands/console.rb:9:in `start'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands.rb:64:in `&lt;top (required)&gt;'
  from bin/rails:4:in `require'
  from bin/rails:4:in `&lt;main&gt;'
  2.0.0-p353 :034 &gt; r.lpush(foo,'bar')
  NameError: undefined local variable or method `foo' for main:Object
  from (irb):34
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands/console.rb:90:in `start'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands/console.rb:9:in `start'
  from /home/poorva/.rvm/gems/ruby-2.0.0-p353/gems/railties-4.0.0/lib/rails/commands.rb:64:in `&lt;top (required)&gt;'
  from bin/rails:4:in `require'
  from bin/rails:4:in `&lt;main&gt;'
  </code></pre>