[#473] Implement EigenTrust calculations

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/reputation/eigentrust/storage/consumers/storage.go

@@ -0,0 +1,40 @@
+package consumerstorage
+
+import (
+	"sync"
+)
+
+// Prm groups the required parameters of the Storage's constructor.
+//
+// All values must comply with the requirements imposed on them.
+// Passing incorrect parameter values will result in constructor
+// failure (error or panic depending on the implementation).
+//
+// The component is not parameterizable at the moment.
+type Prm struct{}
+
+// Storage represents in-memory storage that of the trusts
+// of the consumer peers.
+//
+// It maps epoch numbers to the repositories of intermediate
+// trusts of the consumers of the daughter peers.
+//
+// For correct operation, Storage must be created
+// using the constructor (New) based on the required parameters
+// and optional components. After successful creation,
+// Storage is immediately ready to work through API.
+type Storage struct {
+	mtx sync.RWMutex
+
+	mItems map[uint64]*iterationConsumersStorage
+}
+
+// New creates a new instance of the Storage.
+//
+// The created Storage does not require additional
+// initialization and is completely ready for work.
+func New(_ Prm) *Storage {
+	return &Storage{
+		mItems: make(map[uint64]*iterationConsumersStorage),
+	}
+}