Added an API listener

listeners/handlers/handlers.go

@@ -0,0 +1,14 @@
+package handlers
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/uptrace/bun"
+)
+
+var DB *bun.DB
+
+func HomePage(ctx *gin.Context) {
+	ctx.JSON(http.StatusOK, gin.H{"message": "Welcome to the Receipt Tracker API"})
+}