Redmine

The previous version is 1.4. I am on ubuntu 13.0 and upgrade to 2.3

it report
A source file that the application requires, is missing.
It is possible that you didn't upload your application files correctly. Please check whether all your application files are uploaded.
A required library may not installed. Please install all libraries that this application requires.
Further information about the error may have been written to the application's log file. Please check it in order to analyse the problem.
Error message:
Please install the mysql2 adapter: `gem install activerecord-mysql2-adapter` (cannot load such file -- mysql2)

however I did install mysql2
see gem list output

• LOCAL GEMS ***

actionmailer (3.2.13)
actionpack (3.2.13)
activemodel (3.2.13)
activerecord (3.2.13)
activerecord-mysql2-adapter (0.0.3)
activeresource (3.2.13)
activesupport (3.2.13)
arel (3.0.2)
blankslate (2.1.2.4)
builder (3.2.0)
bundler (1.3.5)
coderay (1.0.9)
erubis (2.7.0)
hike (1.2.1)
i18n (0.6.1)
journey (1.0.4)
mail (2.5.4)
memcache-client (1.8.5)
mime-types (1.23)
multi_json (1.3.6)
mysql (2.8.2)
mysql2 (0.3.13)
net-http-persistent (2.8)
net-ldap (0.3.1)
polyglot (0.3.3)
rack (1.5.2)
rack-cache (1.2)
rack-openid (1.3.1)
rack-ssl (1.3.2)
rack-test (0.6.2)
rails (3.2.13)
railties (3.2.13)
rake (10.0.4)
rchardet (1.3)
rdoc (3.9.4)
ruby-hmac (0.4.0)
ruby-openid (2.1.8)
sprockets (2.4.3, 2.1.3)
thor (0.18.1)
tilt (1.3.3)
treetop (1.4.14)
tzinfo (0.3.33)
yajl-ruby (1.1.0)