Added solution code

Solutions/6_15/follow.py

@@ -0,0 +1,17 @@
+# follow.py
+
+import time
+import os
+
+def follow(filename):
+    '''
+    Generator that produces a sequence of lines being written at the end of a file.
+    '''
+    with open(filename,'r') as f:
+        f.seek(0,os.SEEK_END)
+        while True:
+             line = f.readline()
+             if line != '':
+                 yield line
+             else:
+                 time.sleep(0.1)    # Sleep briefly to avoid busy wait