Raise error on unpermitted params.

Fail loudly if we forget to whitelist a param instead of silently
ignoring it.

misc models: convert to strong params.

artist commentaries: convert to strong params.

* Disallow changing or setting post_id to a nonexistent post.

artists: convert to strong params.

* Disallow setting `is_banned` in create/update actions. Changing it
  this way instead of with the ban/unban actions would leave the artist in
  a partially banned state.

bans: convert to strong params.

* Disallow changing the user_id after the ban has been created.

comments: convert to strong params.

favorite groups: convert to strong params.

news updates: convert to strong params.

post appeals: convert to strong params.

post flags: convert to strong params.

* Disallow users from setting the `is_deleted` / `is_resolved` flags.

ip bans: convert to strong params.

user feedbacks: convert to strong params.

* Disallow users from setting `disable_dmail_notification` when creating feedbacks.
* Disallow changing the user_id after the feedback has been created.

notes: convert to strong params.

wiki pages: convert to strong params.

* Also fix non-Builders being able to delete wiki pages.

saved searches: convert to strong params.

pools: convert to strong params.

* Disallow setting `post_count` or `is_deleted` in create/update actions.

janitor trials: convert to strong params.

post disapprovals: convert to strong params.

* Factor out quick-mod bar to shared partial.
* Fix quick-mod bar to use `Post#is_approvable?` to determine visibility
  of Approve button.

dmail filters: convert to strong params.

password resets: convert to strong params.

user name change requests: convert to strong params.

posts: convert to strong params.

users: convert to strong params.

* Disallow setting password_hash, last_logged_in_at, last_forum_read_at,
  has_mail, and dmail_filter_attributes[user_id].

* Remove initialize_default_image_size (dead code).

uploads: convert to strong params.

* Remove `initialize_status` because status already defaults to pending
  in the database.

tag aliases/implications: convert to strong params.

tags: convert to strong params.

forum posts: convert to strong params.

* Disallow changing the topic_id after creating the post.
* Disallow setting is_deleted (destroy/undelete actions should be used instead).
* Remove is_sticky / is_locked (nonexistent attributes).

forum topics: convert to strong params.

* merges https://github.com/evazion/danbooru/tree/wip-rails-5.1
* lock pg gem to 0.21 (1.0.0 is incompatible with rails 5.1.4)
* switch to factorybot and change all references

Co-authored-by: r888888888 <r888888888@gmail.com>
Co-authored-by: evazion <noizave@gmail.com>

add diffs

db/migrate/20171106075030_add_tag_count_meta_to_posts.rb

@@ -1,4 +1,4 @@
-class AddTagCountMetaToPosts < ActiveRecord::Migration
+class AddTagCountMetaToPosts < ActiveRecord::Migration[4.2]
   def change
     Post.without_timeout do
       add_column :posts, :tag_count_meta, :integer, default: 0, null: false

db/migrate/20171127195124_add_trigram_index_to_tags.rb

@@ -1,4 +1,4 @@
-class AddTrigramIndexToTags < ActiveRecord::Migration
+class AddTrigramIndexToTags < ActiveRecord::Migration[4.2]
   def up
   	Tag.without_timeout do
 	    execute "create index index_tags_on_name_trgm on tags using gin (name gin_trgm_ops)"

db/migrate/20171218213037_add_metadata_to_post_replacements.rb

@@ -1,4 +1,4 @@
-class AddMetadataToPostReplacements < ActiveRecord::Migration
+class AddMetadataToPostReplacements < ActiveRecord::Migration[4.2]
   def change
     PostReplacement.without_timeout do
       add_column :post_replacements, :file_ext_was, :string

db/migrate/20171219001521_add_is_public_to_favorite_groups.rb

@@ -1,4 +1,4 @@
-class AddIsPublicToFavoriteGroups < ActiveRecord::Migration
+class AddIsPublicToFavoriteGroups < ActiveRecord::Migration[4.2]
   def change
     FavoriteGroup.without_timeout do
       add_column :favorite_groups, :is_public, :boolean, default: false, null: false

db/migrate/20171230220225_change_timestamps_to_non_null_on_tags.rb

@@ -1,4 +1,4 @@
-class ChangeTimestampsToNonNullOnTags < ActiveRecord::Migration
+class ChangeTimestampsToNonNullOnTags < ActiveRecord::Migration[4.2]
   def change
     Post.without_timeout do
       change_column_null :tags, :created_at, false

db/migrate/20180113211343_add_category_to_mod_actions.rb

@@ -1,4 +1,4 @@
-class AddCategoryToModActions < ActiveRecord::Migration
+class AddCategoryToModActions < ActiveRecord::Migration[4.2]
   def change
     ModAction.without_timeout do
       add_column :mod_actions, :category, :integer

db/migrate/20180116001101_add_keeper_data_to_posts.rb

@@ -1,5 +0,0 @@
-class AddKeeperDataToPosts < ActiveRecord::Migration
-  def change
-    add_column :posts, :keeper_data, :text
-  end
-end

db/migrate/20180403231351_change_post_flags_reason_type.rb

@@ -1,4 +1,4 @@
-class ChangePostFlagsReasonType < ActiveRecord::Migration
+class ChangePostFlagsReasonType < ActiveRecord::Migration[4.2]
   def change
     change_column :post_flags, :reason, :text
     change_column :post_appeals, :reason, :text