restore index size, try converting to mariadb in CI

ref #296

.travis.yml

@@ -3,9 +3,8 @@ language: csharp
 mono: none
 dotnet: 2.1.403
 solution: FilterLists.sln
-services:
-  - mysql
 addons:
+  mariadb: '10.3.10'
   apt:
     packages:
       - sshpass

src/FilterLists.Api/Migrations/20181019141708_AddRuleRawIndex.cs

@@ -11,7 +11,7 @@ protected override void Up(MigrationBuilder migrationBuilder)
                 "IX_rules_Raw",
                 "rules",
                 "Raw",
-                10); //191);
+                3072);
         }
 
         protected override void Down(MigrationBuilder migrationBuilder)