wip: add api auth and /resume endpoint

internal/delivery/http/v1/usage.go

@@ -0,0 +1,25 @@
+package v1
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func (h *Handler) getUsage(c *gin.Context) {
+	c.Writer.Header().Set("Content-Type", "text/plain")
+	message := fmt.Sprintf(`
+Hello! If you're seeing this message it means you are authorized to view my CV.
+You should have been provided an api key in order to query the different endpoints,
+which are not public. You can put the key into a X-API-KEY header or use it
+as a query param. Examples:
+
+	curl %s/api/v1/usage -H  "X-API-KEY: verysecret"
+
+	curl %s/api/v1/usage?api_key=verysecret
+
+`, c.Request.Host, c.Request.Host)
+
+	c.String(http.StatusOK, message)
+}