[Issue ordering] Using integer instead of float

app/models/concerns/relative_positioning.rb

 module RelativePositioning
   extend ActiveSupport::Concern
 
-  MIN_POSITION = Float::MIN
-  MAX_POSITION = Float::MAX
+  MIN_POSITION = 0
+  MAX_POSITION = Gitlab::Database::MAX_INT_VALUE
 
   included do
     after_save :save_positionable_neighbours
@@ -120,7 +120,7 @@ module RelativePositioning
   def position_between(pos_before, pos_after)
     pos_before, pos_after = [pos_before, pos_after].sort
 
-    rand(pos_before.next_float..pos_after.prev_float)
+    rand(pos_before.next..pos_after.pred)
   end
 
   def save_positionable_neighbours

db/migrate/20170131221752_add_relative_position_to_issues.rb

@@ -24,7 +24,7 @@ class AddRelativePositionToIssues < ActiveRecord::Migration
   # disable_ddl_transaction!
 
   def change
-    add_column :issues, :relative_position, :float
+    add_column :issues, :relative_position, :integer
 
     add_index :issues, :relative_position
   end

db/schema.rb

@@ -515,7 +515,7 @@ ActiveRecord::Schema.define(version: 20170216141440) do
     t.text "title_html"
     t.text "description_html"
     t.integer "time_estimate"
-    t.float "relative_position"
+    t.integer "relative_position"
   end
 
   add_index "issues", ["assignee_id"], name: "index_issues_on_assignee_id", using: :btree