Caching policies added.

We used httpcache library to implement this. As it was not possible to support different policies, I mostly copied and modified it.

cache/leveldbcache/leveldbcache_test.go

@@ -0,0 +1,24 @@
+package leveldbcache
+
+import (
+	"github.com/geziyor/geziyor/cache"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestDiskCache(t *testing.T) {
+	tempDir, err := ioutil.TempDir("", "cache")
+	if err != nil {
+		t.Fatalf("TempDir: %v", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	c, err := New(filepath.Join(tempDir, "Db"))
+	if err != nil {
+		t.Fatalf("New leveldb,: %v", err)
+	}
+
+	cache.PleaseCache(t, c)
+}