assigning exercises

Rewritten-docs.md

@@ -1637,7 +1637,7 @@ we will re-evaluate this decision.
 
 #### Communication with the backend
 
-##### Backend failiure reporting
+##### Backend failure reporting
 
 The backend is a separate component which does not communicate with the
 administrators directly. When it encounters an error it stores it in a log file.
@@ -1805,6 +1805,10 @@ They can be shared by the teachers using an exercise database in ReCodEx.
 
 **Assignment** -- An exercise assigned to a group, possibly with modifications.
 
+**Runtime environment** -- @todo
+
+**Hardware group** -- @todo
+
 ## General basics
 
 Description of general basics which are the same for all users of ReCodEx web
@@ -2093,14 +2097,26 @@ In meta information form you can fill these options:
 Form has to be submitted with "Edit settings" button otherwise changes will not
 be saved.
 
-The same form serves also for the purpose of assignment editation, not only
-creation. That is why on the bottom of the page "Delete the assignment" box can
-be found. Clearly the button "Delete" in there can be used to unassign exercise
-from group.
-
-Let us take a look at time and memory limits form...
-
-@todo: limits
+The same editation page serves also for the purpose of assignment editation, not
+only creation. That is why on the bottom of the page "Delete the assignment" box
+can be found. Clearly the button "Delete" in there can be used to unassign
+exercise from group.
+
+The last unexplored area is time and memory limits form. The whole form is
+situated in box with tabs which are leading to particular runtime environments.
+If you wish to not use one of these, locate "Remove" button at the bottom of the
+box tab which will delete this environment from assignment. Please note that
+this action is irreversible.
+
+In general one tab in environments box contains some basic information about
+runtime environment and another nested tabbed box. In there you can find all
+hardware groups which are available for exercise and you can set here particular
+limits for all test cases. Time and memory limits can be set to all test cases,
+time limits have to be filled in seconds (float), memory limits are in bytes
+(int). If you are interested in some reference values to particular test case
+then you can take a peek on collapsable "Reference solutions' evaluations" item.
+If you are satisfied with changes you made to limits save form with "Change
+limits" button right under environments box.
 
 ### Students' solutions management