README.md in hbtrack-0.0.2 vs README.md in hbtrack-0.0.3

@@ -43,9 +43,45 @@
 To look at individual habit progress:
 ```
 hbtrack list habit_name
 ```
 
+## Limitations
+
+For the current version, some invalid inputs are not handled properly.
+
+## Data
+
+All the data is stored in your home directory, in a hidden file named `.habit`. In Unix/Unix-like system, you can directly edit the file by:
+
+```
+vim ~/.habit
+
+```
+
+All the data is stored in the form of:
+
+```
+workout
+2017,6: 111111100000110100110000000001
+2017,7: 11111111111111111111
+```
+
+The first line represent the name of the habit. The second rows onward represent the progress of the habit for each month. More details:
+
+* `2017,6` represent your progress during June 2017. 
+* `1` is used to represent done.
+* `0` is used to represent undone.
+* Each habit is seperated by a newline. For example:
+
+```
+workout
+2017,7: 11111111111111111111
+
+read
+2017,7: 11111111111110011111
+```
+
 ## Bugs/Features
 If there are any bugs/feature requesst, feel free to create a new issues.