mark post digest and title as required
bugfix
edit post factory
add some examples to admin posts controller spec
render post not valid flash message
bugfix
add translation to post title and digest blank error
render edit on post update if post is not valid
Merge branch 'validate_posts' into develop
migrate database to postgresql
add tags field to posts
test post tags
add tags to post factory
add find_by_tag to posts
fix post factory
change digest field from string to text
make find_by_tag a class method
implement Post#find_by_tag
test submitting tags as arrays
change posts_controller params to get tags string and make an array from them