Allow to associate tags to colors

The color is then used as background in the board, list and task details
views

app/Schema/Sql/mysql.sql

@@ -522,6 +522,7 @@ CREATE TABLE `tags` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `name` varchar(191) COLLATE utf8mb4_unicode_ci NOT NULL,
   `project_id` int(11) NOT NULL,
+  `color_id` varchar(50) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
   PRIMARY KEY (`id`),
   UNIQUE KEY `project_id` (`project_id`,`name`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

app/Schema/Sql/postgres.sql

@@ -927,7 +927,8 @@ ALTER SEQUENCE "swimlanes_id_seq" OWNED BY "swimlanes"."id";
 CREATE TABLE "tags" (
     "id" integer NOT NULL,
     "name" character varying(255) NOT NULL,
-    "project_id" integer NOT NULL
+    "project_id" integer NOT NULL,
+    "color_id" character varying(255)
 );