Merge pull request #11 from mikhail-aksenov/dev-nd

Fixed user adding error. Cancan -> cancancan
Merge pull request #12 from mikhail-aksenov/dev-ma

Dev ma
Merge pull request #13 from mikhail-aksenov/dev-nd

Dev nd
Merge branch 'master' into dev-ma
Merge branch 'dev-ma'
Fixed backward compatibility for category_tag
Merge branch 'master' into dev-ma
Search implemented