updates readme

projects/README.rst

@@ -6,6 +6,15 @@ projects.
 The recommendations may be periodically updated, so please revisit it
 regularly.
 
+0. **Prerequisites**
+
+   Before using TurTLE for production work, you should have passed an
+   "Introduction to programming" class, and you should be familiar with
+   basic concepts of numerical analysis (e.g. "numerical integration"
+   and "FFT").
+   If this is not the case, please discuss this point with your
+   supervisor as soon as possible.
+
 1. **Identify the relevant mathematical entities**.
 
    TurTLE is a fairly generic solver, mostly implementing basic
@@ -14,7 +23,7 @@ regularly.
    For example, numerical representations of scalar fields are
    available, as well as the capability of computing arbitrary
    expressions involving these scalar fields; however there is no
-   "apply Laplacean operator" functionality available.
+   "apply Laplacean operator" functionality available by default.
 
    To this end, it helps to clearly and succinctly state the equations to
    be solved, as well as the quantities that need to be measured from