Rubocop updates (#1118)

* Minimal code style enforcement

* Formatting and lint code updates (no change in functionality)

app/models/period.rb

@@ -1,35 +1,35 @@
 class Period
-    attr_reader :name, :date_range
+  attr_reader :name, :date_range
 
-    def self.find_by_name(name)
-        INDEX[name]
-    end
-
-    def self.names
-        INDEX.keys.sort
-    end
-
-    def initialize(name: "custom", date_range:)
-        @name = name
-        @date_range = date_range
-    end
-
-    def extend_backward(duration)
-        Period.new(name: name + "_extended", date_range: (date_range.first - duration)..date_range.last)
-    end
-
-    BUILTIN = [
-        new(name: "all", date_range: nil..Date.current),
-        new(name: "last_7_days", date_range: 7.days.ago.to_date..Date.current),
-        new(name: "last_30_days", date_range: 30.days.ago.to_date..Date.current),
-        new(name: "last_365_days", date_range: 365.days.ago.to_date..Date.current)
-    ]
-
-    INDEX = BUILTIN.index_by(&:name)
-
-    BUILTIN.each do |period|
-        define_singleton_method(period.name) do
-            period
-        end
+  def self.find_by_name(name)
+    INDEX[name]
+  end
+
+  def self.names
+    INDEX.keys.sort
+  end
+
+  def initialize(name: "custom", date_range:)
+    @name = name
+    @date_range = date_range
+  end
+
+  def extend_backward(duration)
+    Period.new(name: name + "_extended", date_range: (date_range.first - duration)..date_range.last)
+  end
+
+  BUILTIN = [
+      new(name: "all", date_range: nil..Date.current),
+      new(name: "last_7_days", date_range: 7.days.ago.to_date..Date.current),
+      new(name: "last_30_days", date_range: 30.days.ago.to_date..Date.current),
+      new(name: "last_365_days", date_range: 365.days.ago.to_date..Date.current)
+  ]
+
+  INDEX = BUILTIN.index_by(&:name)
+
+  BUILTIN.each do |period|
+    define_singleton_method(period.name) do
+      period
     end
+  end
 end