refactors lock tries [#279]

app/models/lock.rb

@@ -0,0 +1,30 @@
+class Lock < ActiveRecord::Base
+  belongs_to :user
+
+  before_save :set_locked_until
+
+  def locked?
+    locked_until > Time.now
+  end
+
+  def set_locked_until
+    self.locked_until = lock_time if too_many_tries?
+  end
+
+  def lock_time
+    Time.now + (2**tries).minutes
+  end
+
+  def too_many_tries?
+    return false unless tries > 0
+    tries % Lock.max_tries == 0
+  end
+
+  def self.increase_tries(user)
+    Lock.find_or_create_by(user: user).increment!(:tries)
+  end
+
+  def self.max_tries
+    5
+  end
+end