Add Task DB implementation using a local BoltDB.

build_scheduler/go/db/memory_test.go

Index: build_scheduler/go/db/memory_test.go
diff --git a/build_scheduler/go/db/memory_test.go b/build_scheduler/go/db/memory_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..bb27e2f01d5dbdbd2650f0e9e8ab82bd3c20fc13
--- /dev/null
+++ b/build_scheduler/go/db/memory_test.go
@@ -0,0 +1,11 @@
+package db
+
+import "testing"
+
+func TestInMemoryDB(t *testing.T) {
+	TestDB(t, NewInMemoryDB())
+}
+
+func TestInMemoryTooManyUsers(t *testing.T) {
+	TestTooManyUsers(t, NewInMemoryDB())
+}