Rename 'MapDS' to 'JsonDS'; Added some docs

internal/datastore/json_datastore/map_datastore.go

@@ -0,0 +1,34 @@
+package jsondatastore
+
+import "github.com/pikami/cosmium/internal/datastore"
+
+type JsonDataStore struct {
+	storeState State
+
+	initialDataFilePath string
+	persistDataFilePath string
+}
+
+type JsonDataStoreOptions struct {
+	InitialDataFilePath string
+	PersistDataFilePath string
+}
+
+func NewJsonDataStore(options JsonDataStoreOptions) *JsonDataStore {
+	dataStore := &JsonDataStore{
+		storeState: State{
+			Databases:            make(map[string]datastore.Database),
+			Collections:          make(map[string]map[string]datastore.Collection),
+			Documents:            make(map[string]map[string]map[string]datastore.Document),
+			Triggers:             make(map[string]map[string]map[string]datastore.Trigger),
+			StoredProcedures:     make(map[string]map[string]map[string]datastore.StoredProcedure),
+			UserDefinedFunctions: make(map[string]map[string]map[string]datastore.UserDefinedFunction),
+		},
+		initialDataFilePath: options.InitialDataFilePath,
+		persistDataFilePath: options.PersistDataFilePath,
+	}
+
+	dataStore.InitializeDataStore()
+
+	return dataStore
+}