hello world program (#6)

* hello example

* out dir

* README

* Update README.md

* Update hello/README.md

Co-Authored-By: Jakub Konka <kubkon@jakubkonka.com>

* Update task.json

* Add files via upload

* Add files via upload

hello/README.md

@@ -0,0 +1,26 @@
+It is simple hello world gWASM program. Download the `hello` directory, enter it, update paths in `task.json` file
+```
+        "input_dir": "/path/to/your/working/directory/hello/in",
+        "output_dir": "/path/to/your/working/directory/hello/out",
+```
+and execute the command
+```
+golemcli tasks create task.json
+```
+
+If datadir cannot be found, then
+```
+golemcli tasks create task.json --datadir=/path/to/your/datadir
+```
+
+If golemcli cannot be found, then please read [Golem docs](https://docs.golem.network/#/Products/Brass-Beta/Command-line-interface) on how to use golemcli.
+
+After a while check the output
+```
+cat out/subtask1/out.txt 
+```
+
+It should contain
+```
+hello world!
+```

hello/hello.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main(int argc, char** argv) {
+  char* name = argc >= 2 ? argv[1] : "anonymous";
+
+  FILE* f_out = fopen("out.txt", "w");
+  if (f_out == NULL) {
+    printf("couldn't open file for writing\n");
+    return 1;
+  }
+
+  fprintf(f_out, "hello %s!\n", name);
+
+  fclose(f_out);
+
+  return 0;
+}