Dashboard View and Calculations (#521)

* Handle Turbo updates with tabs

Fixes #491

* Add Filterable concern for controllers

* Add trendline chart

* Extract common UI to partials

* Series refactor

* Put placeholders for calculations in

* Add classification generated column to account

* Add basic net worth calculation

* Add net worth tests

* Get net worth graph working

* Fix lint errors

* Implement asset grouping query

* Make trends and series more intuitive

* Fully functional dashboard

* Remove logging

test/models/trend_test.rb

@@ -0,0 +1,37 @@
+require "test_helper"
+
+class TrendTest < ActiveSupport::TestCase
+  test "up" do
+    trend = Trend.new(current: 100, previous: 50)
+    assert_equal "up", trend.direction
+  end
+
+  test "down" do
+    trend = Trend.new(current: 50, previous: 100)
+    assert_equal "down", trend.direction
+  end
+
+  test "flat" do
+    trend = Trend.new(current: 100, previous: 100)
+    assert_equal "flat", trend.direction
+  end
+
+  test "infinitely up" do
+    trend1 = Trend.new(current: 100, previous: nil)
+    trend2 = Trend.new(current: 100, previous: 0)
+    assert_equal "up", trend1.direction
+    assert_equal "up", trend2.direction
+  end
+
+  test "infinitely down" do
+    trend1 = Trend.new(current: nil, previous: 100)
+    trend2 = Trend.new(current: 0, previous: 100)
+    assert_equal "down", trend1.direction
+    assert_equal "down", trend2.direction
+  end
+
+  test "empty" do
+    trend = Trend.new
+    assert_equal "flat", trend.direction
+  end
+end