Update README.md

Should this be "Deleting own posts"? Deleting own topics is already mentioned under "Topics".
NilUser inherits from Forem.user_class

Topic#set_first_post_user expects Forem.user_class
[b] Fix migrations

- No column title when rollback to rename_title_to_name_on_forem_forums then migrate again
Bump to 4.1.7
Support any Rails 4.0 and less than 4.2
polish translation equal to english
Merge pull request #620 from h3xed/polish_translation

polish translation equal to english
Merge pull request #562 from chrisalley/patch-1

Update README.md
Add regression spec for #584
Merge pull request #618 from hieuk09/fix_migration_error_add_forem_views_fields

[b] Fix migrations
Merge pull request #584 from alexcwatt/niluser

NilUser inherits from Forem.user_class
Fix a few sorting issues: * default Category sorting to "position ASC", same as with the Forum model * allow forums "position" to be mass-assigned
Add a test for forum_params in Admin::ForumsController
Removed the default scope from Forem::Category and added a by_position scope instead.
Support Ruby 2.1.5 + Remove 1.9.3 and jruby from Travis

1.9.3 is unsupported by Ruby Core.

JRuby constantly errors on Travis, and although we'll be keeping support for it I want the errors to go away.
Reduce before_filter abuse in PostsController
Merge branch 'rails4' of git://github.com/radar/forem into rails4