Refactor and remove sqlite and replace with MySQL

internal/models/statistics.go

@@ -0,0 +1,18 @@
+package models
+
+type TopNum struct {
+	Number    int
+	Frequency int
+}
+
+type Pair struct {
+	A         int
+	B         int
+	Frequency int
+}
+
+type ZScore struct {
+	Ball   int
+	Recent int
+	Z      float64
+}