In sign up form, merge PhD-science and PhD-other, add Associate's degree

Includes corresponding documentation changes.

Per request from Harvard: LH #276

common/djangoapps/student/models.py

@@ -75,10 +75,15 @@ class UserProfile(models.Model):
     GENDER_CHOICES = (('m', 'Male'), ('f', 'Female'), ('o', 'Other'))
     gender = models.CharField(blank=True, null=True, max_length=6, db_index=True,
                               choices=GENDER_CHOICES)
-    LEVEL_OF_EDUCATION_CHOICES = (('p_se', 'Doctorate in science or engineering'),
-                                  ('p_oth', 'Doctorate in another field'),
+
+    # [03/21/2013] removed these, but leaving comment since there'll still be
+    # p_se and p_oth in the existing data in db.
+    # ('p_se', 'Doctorate in science or engineering'),
+    # ('p_oth', 'Doctorate in another field'),
+    LEVEL_OF_EDUCATION_CHOICES = (('p', 'Doctorate'),
                                   ('m', "Master's or professional degree"),
                                   ('b', "Bachelor's degree"),
+                                  ('a', "Associate's degree"),
                                   ('hs', "Secondary/high school"),
                                   ('jhs', "Junior secondary/junior high/middle school"),
                                   ('el', "Elementary/primary school"),

doc/public/internal_data_formats/sql_schema.rst

@@ -313,14 +313,18 @@ There is an important split in demographic data gathered for the students who si
        - This student signed up before this information was collected
      * - `''` (blank)
        - User did not specify level of education.
+     * - `'p'`
+       - Doctorate
      * - `'p_se'`
-       - Doctorate in science or engineering
+       - Doctorate in science or engineering (no longer used)
      * - `'p_oth'`
-       - Doctorate in another field
+       - Doctorate in another field (no longer used)
      * - `'m'`
        - Master's or professional degree
      * - `'b'`
        - Bachelor's degree
+     * - `'a'`
+       - Associate's degree
      * - `'hs'`
        - Secondary/high school
      * - `'jhs'`
@@ -624,4 +628,4 @@ The generatedcertificate table tracks certificate state for students who have be
 
 `grade`
 -------
-  The grade of the student recorded at the time the certificate was generated. This may be different than the current grade since grading is only done once for a course when it ends.
+  The grade of the student recorded at the time the certificate was generated. This may be different than the current grade since grading is only done once for a course when it ends.
\ No newline at end of file