Add Live Data to Account Page (#464)

* Add trends, time series, seed data

* Remove test data

* Replace old view values with helpers

* Fix tooltip bugs in D3 chart

* Fix tests

* Fix smoke test

* Add CRUD actions for valuations

* Scaffold out inline editing with Turbo

app/models/trend.rb

@@ -0,0 +1,26 @@
+class Trend
+    attr_reader :current, :previous
+
+    def initialize(current, previous)
+        @current = current
+        @previous = previous
+    end
+
+    def direction
+        return "flat" unless @previous
+        return "up" if @current > @previous
+        return "down" if @current < @previous
+        "flat"
+    end
+
+    def amount
+      return 0 if @previous.nil?
+      @current - @previous
+    end
+
+    def percent
+      return 0 if @previous.nil?
+      return Float::INFINITY if @previous == 0
+      ((@current - @previous).abs / @previous.to_f * 100).round(1)
+    end
+end