fix: allow passing absolute and relative path as userAppDir option (#515)

Author: Alex Chaplinsky

src/util.ts

@@ -181,7 +181,7 @@ export async function statOrNull(file: string): Promise<Stats | null> {
 
 export async function computeDefaultAppDirectory(projectDir: string, userAppDir: string | null | undefined): Promise<string> {
   if (userAppDir != null) {
-    const absolutePath = path.join(projectDir, userAppDir)
+    const absolutePath = path.resolve(projectDir, userAppDir)
     const stat = await statOrNull(absolutePath)
     if (stat == null) {
       throw new Error(`Application directory ${userAppDir} doesn't exists`)
@@ -227,4 +227,4 @@ export function getTempName(prefix?: string | n): string {
 
 export function isEmptyOrSpaces(s: string | n) {
   return s == null || s.trim().length === 0
-}
+}