add oneliner to combine forks from two runs

docs/oneliners.md

@@ -26,7 +26,7 @@ $ jq '
 * Find all students present in multiple groups
 
 ```sh
-$ jq '.[] | .members | map(.name) | .[]' forks.json \
+$ jq '.[].members[].name' forks.json \
   | sort \
   | uniq -dc
 
@@ -39,10 +39,15 @@ $ jq '.[] | .members | map(.name) | .[]' forks.json \
 # 1. Get the list of students in groups, sort it
 # 2. Sort the list of all enrolled students
 # 3. Find names which are in enrolled students, but not grouped students
-jq '.[] | .members | map(.name) | .[]' forks.json \
+$ jq '.[].members[].name' forks.json \
   | sort \
-  | uniq -d \
-  | sed 's/^ *//' \
   | comm -23 <( sort enrolled_students.txt) -
+
 "John Smith"
 ```
+
+* Combine forks from two different runs into a single json (for groups present in both files, the entry from run1.json is selected).
+
+```sh
+jq -s '.[0] + .[1] | unique_by(.group)' run1.json run2.json > both_runs.json
+```